LIBRARY 


UNIVERSITY  OF  CALIFORNIA. 


Class 


SEHERAE 


GENERAL  SPECIFICATIONS 

FOR 

STEEL  RAILROAD  BRIDGES 


AND  STRUCTURES 


WITH  A  SECTION  MAKING  THEM  APPLICABLE  TO 

HIGHWAY  BRIDGES  AND  BUILDINGS 


PREPARED  UNDER  THE  DIRECTION  OF 

VIRGIL  Q.  BOGUE 

CIVIL  ENGINEER 

BY 

ALBERT  W-LBUEL 


ASSOCIATE  ON  BRIDGES 

15  WILLIAM  STREET,  NEW  YORK 


NEW  YORK 
THE  ENGINEERING  NEWS  PUBLISHING  COflPANY 

1906 


GENERAL  SPECIFICATIONS 

FOR 

STEEL  RAILROAD  BRIDGES 


AND  STRUCTURES 

WITH  A  SECTION  MAKING  THEM  APPLICABLE  TO 

HIGHWAY  BRIDGES  AND  BUILDINGS 


PREPARED  UNDER  THE  DIRECTION  OF 

VIRGIL  Q.  BOQUE 

CIVIL   ENGINEER 

BY 

ALBERT  W.  BUEL 

ASSOCIATE  ON   BRIDGES 
15  WILLIAM  STREET,  NEW  YORK 


NEW  YORK 

THE  ENGINEERING   NEWS  PUBLISHING   COflPANY 

1906 


GENERAL 


Copyright,  1906,  by 
THE  ENGINEERING  NEWS  PUBLISHING  COMPANY 


J,   F.    TAPLEY  CO. 

PRINTERS   AND   BINDERS 

NEW  YORK 


PREKACB. 

These  Specifications  have  been  written  with  the  purpose  of 
combining  such  rules,  governing  the  design,  workmanship  and 
quality  of  material,  that  steel  structures  built  in  accordance  with 
them  will  be  first-class  in  every  respect,  up  to  the  highest  stan- 
dard of  present  practice,  and  at  the  same  time  as  economical 
as  is  consistent  with  such  results. 

During  the  past  three  years,  a  very  considerable  tonnage  has 
been  built  under  specifications  not  differing  materially  from  these 
here  presented.  This  included  many  different  types  of  railroad 
bridges,  swing  spans,  highway  bridges  and  railroad  buildings 
and  sheds.  The  entirely  satisfactory  results  obtained,  without 
any  of  the  misunderstandings  or  special  interpretations  so  often 
attending  such  work,  seem  to  justify  the  hope  that,  rewritten  in 
a  general  form  and  revised  after  three  years'  use,  they  may  be 
of  some  assistance  and  value  to  bridge  builders.  If  this  is  real- 
ized, the  writer  will  be  fully  compensated. 

While  endeavoring  to  make  them  conform  with  the  most  recent 
practice  and  experience,  innovations  that  have  not  been  fully 
demonstrated  as  improvements  on  older  forms  have  been  avoided. 
Thus,  in  carrying  out  this  aim,  the  Cain-Launhardt  formula  has 
been  retained  in  preference  to  the  Snyder-Thompson  impact  for- 
mula, but  so  changed  in  form  that  it  governs  the  proportions  of 
all  details,  including  the  bearing  and  shear  on  rivets,  pins  and 
web  plates.  This  is  thought  to  be  an  improvement  on  the  older 
form  of  this  formula,  and  is  more  rational.  It  takes  into  account 
the  ratio  of  dead  to  live  load,  so  that,  for  example,  the  addition 
for  impact  is  less  in  the  case  of  a  structure  with  a  ballast  floor 
than  where  a  lighter  floor  is  used.  In  this  respect  it  is  thought 
to  be  better  than  the  Snyder-Thompson  formula. 

The  "Quality  of  Material,"  specified  in  Section  VI,  is  first- 
class  in  every  respect,  but  such  as  can  be  readily  obtained  in  any 
of  the  American  mills,  without  extra  cost. 

161365 


The  ''Workmanship,"  specified  in  Section  VII,  can  be  com- 
plied with  by  all  well-equipped  shops.  Class  C  workmanship  (see 
Paragraph  i)  is  the  minimum  that  should  be  accepted  for  struc- 
tures carrying  railroad  tracks.  Class  B  workmanship  is  what  is 
known  as  that  requiring  general  reaming,  and  would  probably 
cost  from  $1.50  to  $3.00  per  ton  more  than  Class  C,  but,  in  the 
opinion  of  many  engineers,  including  the  writer,  it  is  worth  the 
difference  in  cost.  Class  A  workmanship,  in  addition  to  general 
reaming,  requires  material  f  of  an  inch  thick,  or  over,  to  be 
drilled  from  the  solid.  Except  for  very  long  spans,  or  exceed- 
ingly heavy  structures,  the  practical  effect  of  this  requirement  is 
to  limit  the  thickness  of  the  material  to  a  maximum  of  11/16  of 
an  inch.  Such  a  limitation  is  quite  generally  considered  desira- 
ble. Heavy  work,  necessitating  the  use  of  material  over  11/16  of 
an  inch  thick,  under  Class  A  workmanship,  will  probably  cost 
from  $1.50  to  $3.00  per  ton  more  than  Class  B  workmanship  and 
$3.00  to  $6.00  per  ton  more  than  that  of  Class  C.  For  Highway 
Bridges  and  Buildings  these  requirements  for  workmanship  are 
considerably  reduced.  (See  Paragraphs  156  and  157.) 

The  new  uniform  live  load,  given  in  Paragraph  37,  which  may 
be  substituted  for  the  Cooper  concentrated  loadings,  is  presented 
for  the  use  of  engineers  who  prefer  to  use  uniform  loads,  rather 
than  wheel  loads,  in  their  computations.  It  \vill  give  somewhat 
greater  moments  for  spans  up  to  about  one  hundred  and  fifty  feet 
in  length,  and  slightly  smaller  moments  for  spans  over  four  hun- 
dred feet  in  length,  which  is  considered  an  advantage. 

No  claim  is  made  for  originality  in  these  Specifications.  In 
fact,  the  time  has  long  since  passed  in  which  it  has  been  consis- 
tent, or  even  possible,  to  introduce  much  originality  in  new  speci- 
fications for  structural  steel,  without  greatly  sacrificing  their 
value  and  merit.  Writing  new  specifications  has  become  chiefly 
a  matter  of  selection,  compilation,  arrangement  and  form  of  ex- 
pression. In  the  present  case,  the  writer  makes  general  acknowl- 
edgment for  assistance  to  all  of  the  standard  specifications  which 
liave  preceded  these. 

It  is  believed  that  their  clearness,  wide  range  of  application  and 
number  of  points  covered,  will  fully  compensate  for  their  length. 

Special  acknowledgment  for  assistance  and  advice  in  the  prepa- 


ration  of  this  edition  is  due  to  Mr.  Virgil  G.  Bogue,  under  whose 
direction  and  approval  the  work  has  been  done;  Mr.  J.  C.  Hall- 
sted,  of  Robert  W.  Hunt  &  Company ;  Mr.  J.  Q.  Barlow,  Chief 
Engineer  of  the  Western  Maryland  Railroad;  Mr.  W.  H.  Ken- 
nedy, Consulting  Engineer ;  Mr.  A.  B.  Hager,  Mr.  Thomas  Earle 
and  Mr.  W.  A.  Aycrigg.  A.  W.  B. 

15  William  Street, 
New  York  City. 
Tune,  1906. 


TABLE     OK     CONTENTS. 


SECTION  I. — PRELIMINARIES. 

1.  Proposals  and  Letter  of  Invitation. 

2.  Stress  Sheets  and  General  Plans. 

3.  Increase  or  Decrease  of  Materials. 

4.  Right  to  Reject  Bids. 

5.  Working  Drawings. 

6.  Mill  Orders. 

7.  Changes  in  Drawings. 

8.  Data  for  Masonry  Plans. 

SECTION  II. — GENERAL  REQUIREMENTS. 

9.  Material. 

10.  Types  of  Bridges. 

11.  Clearances. 

Floor  System. 

12.  Cross  Ties. 

13.  Floor  Beams  and  Stringers. 
14  &  15.     Solid  Floors. 

16.  Drainage,  Gutters,  etc. 

Plate  Girders. 

17.  Depth  of  Girders. 

1 8.  Spacing  of  Girders. 

19.  Flanges  and  Stiffeners. 

20.  Splices. 

21.  Top  Lateral  Bracing  in  Deck  Girders. 

22.  Gusset  Plates  in  Half  Through  Girders. 

23.  Hinge  or  Spherical  Bearings. 


8 

24.  Bed  Plates  and  Anchor  Bolts. 

25.  Rounded  Ends. 

Viaducts  and  Trestles. 

26.  General  Design. 

27.  Connections. 

Truss  Bridges. 

28.  Main  Features. 

29.  Riveted  Trusses. 

30.  Pin  Connected  Trusses. 

Movable  Bridges. 

31.  Swing  Bridges. 

32.  Turn  Tables. 

33.  Machinery. 

34.  Lifts  and  Latches. 

35.  Cabin  and  Signal  Lights. 

SECTION  III. — LOADS. 

36.  Dead  Load. 

37.  Live  Load. 

38.  Allowance  for  Impact  or  Dynamic  Effect  of  Live  Loads. 

39.  Allowance  for  Wind  Loads  and  Lateral  Vibration. 

40.  Centrifugal  Force. 

41.  Traction  and  Momentum. 

42.  Thermal  Forces. 

SECTION  IV. — WORKING  STRESSES. 

43.  Tension. 

44.  Compression. 

45.  Combined  Stresses. 

46.  Wind  Stresses. 

47.  Shearing. 

48.  StifTeners. 

49.  Bearing. 

50.  Bending. 

51.  Rivets. 

52.  Timber. 


53-  Unit  Stress  for  Momentum  and  Centrifugal  Force. 

54.  Friction. 

55.  Bearing  on  Rollers  and  Wheels. 

56.  Transverse  Loading. 

SECTION  V. — GENERAL  DETAILS. 

57.  Unsymmetrical  Sections. 

58.  H-Sections. 

59.  Tension  Members. 

60.  Floor  Beam  Connection. 

61.  Bracing.  . 

62.  Lateral  Bracing. 

63.  Top  Lateral  Struts. 

64.  Sway  Bracing. 

65.  Portals. 

66.  Parallel  Deck  Spans. 

67.  Cross  Frames. 

68.  Stringer  Bracing. 

69.  Sections  and  Connection  of  Bracing. 

70.  Minimum  Sections. 

71.  Pins,  Pin  Plates  and  Eye  Bars. 

72.  Shoes,  Bed  Plates  and  Rollers. 

73.  Effective  Diameter  of  Rivets. 

74.  Pitch  of  Rivets. 

75.  Distance  from  Center  of  Rivet  to  Edge  of  Plate. 

76.  Grip  of  Rivets. 

77.  Tie  Plates  and  Lacing. 

78.  Length  of  Tie  Plates. 

79.  Double  Lattice. 

80.  Single  Lacing. 

81.  Width  and  Spacing  of  Bars. 

82.  Bolts. 

83.  Washers  and  Nuts. 

84.  Drainage. 

85.  Turn  Tables  of  Swing  Spans. 

86.  Camber. 

87.  Expansion,. 


10 

SECTION  VI. — QUALITY  OF  MATERIAL. 

Structural  Steel. 

88.  Kind  of  Steel  and  Chemical  Limitation. 

89.  Grades  of  Steel. 

90.  Tensile  Strength  and  Elongation. 

91.  The  Yield  Point. 

92.  Modifications  of  Requirements  for  Elongation. 

93.  Eye  Bar  Tests. 

94.  Bending  and  Drifting  Tests. 

95.  Test  Pieces  and  Methods  of  Testing. 

96.  Tensile  Test  Specimens. 

97.  Bending  Test  Specimens. 

98.  Condition  of  Specimens. 

99.  Chemical  Tests. 

100.  Variation  in  Weight.  ,» 

101.  Finish. 

1 02.  Branding. 

Cast  Steel. 

103.  Process  of  Manufacture. 

104.  Chemical  Properties.   . 

105.  Physical  Properties. '  . 

1 06.  Drop  Test. 

107.  Percussive  Test. 

1 08.  Bending  Test. 

109.  Test  Specimen  for  Tensile  Test. 

no.  Number  and  Location  of  Tensile  Specimens, 

in.  Test  Specimen  for  Bending. 

112.  Yield  Point. 

113.  Sample  for  Chemical  Analysis. 

114.  Finish. 

Cast  Iron. 

115.  Cast  Iron. 

Timber. 

1 1 6.  Timber. 

117.  Creosoted  Timber. 


II 

Paint  and  Oil. 

1 1 8.  Linseed  Oil. 

119.  Iron  Oxide. 

1 20.  Paint. 

121.  Inspection. 

SECTION  VIL— WORKMANSHIP. 

122.  General. 

123.  Drilling. 

124.  Punching  and  Reaming. 

125.  Accuracy. 

126.  Punching  of  Laterals,  etc. 

127.  Planing  Edges. 

128.  Rivets. 

129.  Field  Rivets  and  Bolts. 

130.  Finished  Surfaces,  Joints  and  Fillets. 

131.  Stiff ener  Angles. 

132.  Pins,  Pilots  and  Rollers. 

133.  Pin  Holes. 

134.  Eye  Bars. 

135.  Upset  Ends. 

136.  Screw  Threads. 

137.  Annealing. 

SECTION  VIII. — PAINTING. 

138.  Painting. 

SECTION  IX. — INSPECTION. 

139.  Full  Size  Tests. 

140.  Testing  Machines. 

141.  Access  to  Works. 

142.  Notice. 

143.  Defective  Materials. 

144.  Interpretation  of  Drawings  and  Specifications. 

SECTION  X. — ERECTION. 

145.  Extent  of  the  Work. 

146.  Conditions. 


12 


147-  Watchmen,  Risks,  etc. 

148.  Maintaining  and  Cutting  Track. 

149.  Details  of  Erection. 

150.  When  Railroad  Company  Erects. 

SECTION  XL — HIGHWAY  BRIDGES  AND  BUILDINGS. 

151.  General. 

152.  Loads. 

153.  Working  Unit  Stresses  and  Allowance  for  Impact. 

154.  Sway  Bracing. 

155.  Minimum  Sections. 

156.  Punching  and  Reaming. 

157.  Planing. 

158.  Building  Laws. 


SPECIFICATIONS. 

I. 

PRELIMINARIES. 

Proposals  and  Letter  of  Invitation. 

1.  Bidders  shall  submit  sealed  proposals  in  accordance  with  all 
the  terms  of  the  letter  of  invitation  or  memorandum  for  bidders 
and  of  these  specifications.    All  proposals  for  a  bridge  or  bridges 
or  structures  shall  include  all  bolts  and  lag  screws  for  fastening 
ties  and  guard  rails,  although  the  latter  may  be  furnished  and 
placed  by  the  Railroad  Company,  all  anchor  bolts  and  anchors, 
grillages  to  be  embedded  in  the  masonry,  all  hand  railings  and 
all  other  metal  work  required  in  the  completed  structures.     All 
claims  for  royalties  on  patented  devices  used  in  any  structure 
shall  be  paid  by  contractor. 

The  letter  of  invitation  or  memorandum  for  bidders  will  state 
whether  the  work  is  to  be  of  Class  A,  B  or  C.  For  Class  A  work, 
all  the  requirements  of  paragraphs  123,  124,  125  and  127  shall  be 
complied  with.  For  Class  B  work,  no  drilling  from  the  solid  will 
be  required.  For  Class  C  work,  no  drilling  from  the  solid,  nor 
planing  of  edges,  will  be  required,  and  rivet  holes  need  not  be 
reamed,  except  in  material  over  f  inch  thick,  used  in  tension 
where  sub-punching  and  reaming  will  be  required. 

Terms  or  conditions  of  the  letter  of  invitation  or  memorandum 
for  bidders  conflicting  with  these  specifications  will  supersede 
those  herein  contained  for  the  work  or  structures  referred  to, 
but  no  other. 

Stress  Sheets  and  General  Plans. 

2.  When  not  furnished  by  the  Railroad  Company,  bidders  shall 
submit  with  each  proposal : 


(a).  Full  stress  and  section  sheets,  showing  maximum  and 
minimum  stresses,  moments  and  shears,  and  the  sections  proposed, 
with  all  data  required  for  checking  them. 

(b).  When  specifically  required  by  the  letter  of  invitation  or 
memorandum  for  bidders,  plans,  elevations  and  sections  showing 
the  general  arrangement,  clearances,  character  of  all  details  and 
connections  and  all  sizes  required  from  which  to  make  up  a  de- 
tailed estimate.  These  details  will  generally  be  shown  to  ^-inch 
scale  for  trusses  and  ^-inch  scale  for  girders,  and  shall  give  or 
indicate  the  number  of  rivets  to  be  used  in  each  important  con- 
nection. 

Increase  or  Decrease  of  Materials. 

3.  All  proposals  and  contracts  shall  be  made  on  the  under- 
standing that  the  Railroad  Company  may  increase  or  decrease  the 
amount  of  material  in  any  part  of  the  structure,  the  price  to  be 
paid  on  the  contract  being  increased  or  decreased  by  such  amount 
of  material  at  the  unit  price  named.     For  this  purpose  all  propo- 
sals arid  contracts  made  for  a  lump  sum  shall  contain  a  unit  price 
for  such  increase  or  decrease  in  the  amount  of  material  to  be  used. 
Should  this  unit  price  be  omitted  for  any  cause  from  a  lump  sum 
contract,  it  is  hereby  agreed  that  the  lump  sum  price  divided  by 
the  weight  of  metal  covered  by  it  shall  be  the  price  per  pound  at 
which  any  subsequent  increase  or  decrease  in  the  weight  required 
by  the  Railroad  Company  shall  be  adjusted  in  the  final  payment. 

Right  to  Reject  Bids. 

4.  The  Railroad  Company  reserves  the  right  to  rejec.  any  or 
all  bids. 

Working  Drawings. 

5.  As  soon  as  a  contract  has  been  awarded,  the  contractor 
shall  prepare  a  full  set  of  working  drawings  in  detail,  and  shall 
submit  two  complete  sets  of  blue  prints  to  the  Chief  Engineer  for 
his  approval.    After  the  approval  of  the  drawings,  the  contractor 
shall  furnish  the  Chief  Engineer  with  three  complete  sets  of  the 
blue  prints  for  use  during  construction,  and  after  the  completion 


15 

of  the  work  the  original  tracings  shall  become  the  property  of  the 
Railroad  Company,  and  shall  be  delivered  to  the  Chief  Engineer. 
The  approval  of  the  Chief  Engineer  shall  not  relieve  the  con- 
tractor of  any  responsibility  for  their  accuracy.  The  contractor 
alone  shall  be  responsible  for  the  accuracy  of  drawings  and  work- 
manship. 

Mill  Orders. 

6.  As  soon  as  the  working  drawings  have  been  approved  by 
the  Chief  Engineer,  the  contractor  shall  order  the  material  from 
the  mills.    Any  material  ordered  before  the  approval  of  the  draw- 
ings shall  be  at  the  contractor's  own  risk.    He  shall  immediately 
furnish  the   Chief  Engineer  with   duplicate  copies  of  the  mill 
orders  for  the  use  of  inspectors. 

Changes  in  Drawings. 

7.  No  change  shall  be  made  in  any  drawing  after  it  has  been 
approved  except  by  consent  or  direction,  in  writing,  of  the  Chief 
Engineer. 

Data  for  Masonry  Plans. 

8.  When  not  specified  by  the  Railroad  Company,  the  con- 
tractor shall,  within  15  days  from  the  award  of  contract,  furnish 
all  necessary  data  for  proportioning  the  masonry  work. 


Material. 


II. 
GENERAL   REQUIREMENTS. 


9.  All  structures  shall  be  built  entirely  of  structural  steel  ex- 
cept where  otherwise  specified.     Cast  iron  or  cast  steel  may  be 
used  in  the  machinery  of  movable  bridges  and  in  special  cases  for 
shoes  and  bearings. 

Types  of  Bridges. 

10.  Preference  will  generally  be  given  to  the  following  types 
of  bridges : 

For  spans  up  to  20  feet — Rolled  beams  or  longitudinal  trough 
floors. 

For  spans  from  20  feet  to  100  feet — Plate  girders. 

For  spans  from  100  feet  to  175  feet — Riveted  trusses. 

For  spans  over  175  feet — Pin  connected  trusses. 

These  limits  will  be  modified  as  required  in  specific  cases. 

Double  track  through  bridges  will  generally  have  but  two 
trusses  or  girders  to  avoid  spreading  the  tracks. 

For  the  purpose  of  calculating  stresses,  the  length  of  span 
shall  be  taken  as  the  distance  center  to  center  of  bearing  plates 
for  all  beams  and  girders  and  the  distance  center  to  center  of 
end  pins  for  pin  connected  trusses  and  riveted  trusses  or  girders 
with  hinged  shoes.  For  floor  beams  and  stringers  the  distance 
from  center  to  center  of  trusses,  girders  or  beams  to  which  they 
connect,  will  be  taken  as  the  span. 

Clearances. 

11.  All  through  or  half  through  bridges  on  tangents,   shall 
have  a  clear  opening  not  less  than  that  shown  on  the  accompany- 
ing clearance  diagram.     For  two  or  more  tracks,  the  distance 

from  center  to  center  of  tracks  will  be   On 

curves  the  center  line  of  the  bridge  shall  generally  be  placed 
midway  between  and  parallel  to  the  chord  and  tangent  to  the 


i? 

curve  at  center  of  span,  and  so  as  to  give  equal  clearance  on  each 
side,  and  where  required  to  preserve  the  clearance  dimensions 
shown  on  diagram,  the  clear  width  between  trusses  shall  be  in- 
creased. In  calculating  clearance  for  curvature,  the  super-eleva- 
tion of  the  outer  rail  shall  be  that  obtained  from  the  following 
formula,  with  a  car  80  feet  long  over  platforms  and  59  feet  center 
to  center  of  the  trucks  and  having  a  cross  section  the  same  as  the 
standard  clearance : 

GV2 

E= =r,  with  a  maximum  of  6  inches, 

32.2R' 

where 

E=Elevation  of  outer  rail  in  feet, 

G=Gauge  of  track  in  feet, 

V— Velocity  of  train  in  feet  per  second,  for  a  speed 

of  60 — 3D  miles  per  hour,  D  being  the  degree 

of  curvature, 
R— Radius  of  curve  in  feet. 


FLOOR    SYSTEM. 
Cross  Tics. 

12.  Cross  ties  will  be  of  long  leaf  yellow  pine,  white  oak,  Ore- 
gon fir  (Douglas  fir),  or  pine,  as  may  be  approved  by  the  Chief 
Engineer.  They  shall  not  be  spaced  more  than  6  inches  nor  less 
than  4  inches  apart  in  the  clear.  They  will  have  a  width  of  8 
inches  and  a  depth  depending  upon  the  distance  between  the  cen- 
ters of  supports.  For  6  feet  6  inches  center  to  center  of  the 
supports  they  will  be  8  inches  deep,  and  for  longer  distances  they 
will  have  a  depth  required  by  the  moment  produced  by  60,000 
pounds  on  one  pair  of  wheels,  taken  as  distributed  over  three  ties. 
They  will  generally  be  spaced  12  inches  center  to  center  and 
notched  one-half  inch  over  supports.  In  deck  plate  girders  the 
cross  ties  shall  rest  directly  on  the  top  flange.  Deck  truss  bridges 
will  preferably  be  provided  with  floor  beams  and  stringers,  but 
in  special  cases  the  ties  may  rest  directly  on  the  top  chords.  Ties 
on  deck  plate  girders  shall  be  10  or  12  inches  deep,  when  required 
to  give  at  least  7  inches  over  the  thickest  part  of  the  flange.  The 
super-elevation  of  the  outer  rail  on  curves  will  be  obtained  by 


i8 

using  beveled  ties.  The  Railroad  Company  will  furnish  plans  of 
standard  wooden  decks,  showing  also  super-elevation  of  outer 
rail  on  curves. 

Floor  Beams  and  Stringers. 

13.  The  track  stringers  will  preferably  be  riveted  to  the  webs 
of  floor  beams  and  shall  be  spaced  6  feet  6  inches  center  to  cen- 
ter when  track  is  on  tangent,  with  wider  spacing  when  required 
on  curves.     When  the  length  of  the  stringers  exceeds  12  times 
the  width  of  the  flange,  they  shall  have  their  top  flanges  braced 
together  with  a  system  of  diagonal  lateral  bracing.     Stringer  lat- 
eral bracing  will  be  required  in  all  cases  where  the  alignment  is 
on  a  curve.     Floor  beams  shall  be  riveted  directly  to  girders  or 
trusses.     In  truss  bridges  they  will  generally  be  riveted  between 
the  posts  above  the  bottom  chord.    The  design  of  the  connection 
must  be  such  as  to  practically  avoid  eccentricity.    End  floor  beams 
will  be  required  whenever  practicable.    The  connection  angles  of 
stringers  to  floor  beams  and  floor  beams  to  girders  or  trusses 
shall  in  no  case  be  less  than  3^  inches  by  3^  inches  in  size  nor 
less  than  ^  inch  thick. 

Solid  Floors. 

14.  Solid  floors  will  generally  be  designed  of  rolled  I-beams 
covered  with  a  plate  riveted  to  each  beam.    Where  the  section  of 
the  plate  is  necessary  to  make  up  a  part  of  the  required  moment 
of  inertia  it  shall  not  be  less  than  ^  inch  thick.     In  cases  where 
a  floor  of  minimum  thickness  is  necessary,  trough  floors  may  be 
used.    Troughs  shall  be  built  of  vertical  web  plates  and  horizontal 
flange  plates  connected  by  angles.     Solid  floors  shall  be  connected 
to  girders  or  trusses  by  angles  not  less  in  size  than  3^  inches  by 
3J  inches  by  J  inch  thick.     Each  I-beam  or  each  web  of  trough 
shall  be  connected  to  the  girder  or  truss  at  each  end. 

15.  When  solid  floors  are  used  with  half  through  plate  gird- 
ers, gussets  connecting  the  floor  and  girder  shall  te  placed  at  in- 
tervals of  not  over  12  feet.    They  shall  be  as  wide  at  the  bottom 
as  the  standard  clearance  dimensions  will  permit  and  shall  extend 
to  the  top  flange'  of  the  main  girder. 


'9      . 

Drainage, '  Gutters,  etc. 

1 6.  Provision  for  drainage  of  solid  floor  bridges  shall  be  made, 
subject  to  the  approval  of  the  Chief  Engineer.  Over  streets  or 
roadways  and  in  other  places  when  specially  required,  drainage 
gutters  and  down  spouts  shall  be  furnished.  The  gutters  shall 
be  made  of  No.  20  galvanized  iron,  and  erected  in  a  substantial 
manner.  The  down  spouts  shall  be  4  inches  in  diameter,  of  cast 
iron. 


PLATE    GIRDERS. 
Depth  of  Girders. 

17.  Plate  girders  shall  generally  have  a  depth  of  from  1-8  to 
i- 12  of  the  span.     When  limited  head  room  necessitates  a  less 
depth  than  1-12  of  the  span,  the  girder  shall  be  so  proportioned 
that  the  moment  of  inertia  will  be  the  same  as  would  be  required 
for  a  girder  of  the  same  span  with  a  depth  of  1-12  of  the  span. 

Spacing  of  Girders.  y 

1 8.  Deck  plate  girders  not  over  75  feet  long  will  generally  be 
spaced  6  feet  6  inches  center  to  center,   except  where  greater 
width  is  required  on  curves.     For  girders  over  75  feet  long,  the 
distance  center  to  center  of  girders  shall  not  be  less  than  1-12 
of  the  span. 

Flanges  and  Stiffeners. 

19.  In  girders  with  flange  plates,  the  angles  shall   form  as 
large  a  proportion  of  the  flange  area  as  practicable.   When  flange 
plates  are  not  of  the  same  thickness,  they  shall  diminish  in  thick- 
ness outward  from  the  angles.     The  first  flange  plate  of  the  top 
flange  shall  extend  the  full  length  of  the  girder  and  all  flange 
plates  must  be  at  least  one   foot  longer  than  their  theoretical 
length.     The  webs  of  all  plate  girders  shall  have  stiffeners  over 
bearing  plates  and  at  all  points  of  local  concentrated  loadings. 
The  projecting  leg  of  the  end  stiffeners  shall  be  just  one  size  less 


20 

than  the  horizontal  leg  of  the  flange  angles  and  there  shall  be  two 
angles  over  each  end  of  each  bearing. 

Splices. 

*• 

20.  Web  plates  shall  be  spliced  by  a  plate  on  each  side  with 
sufficient  rivets  and  section  to  transmit  the  shear,  and  in  addition 
shall  be  spliced  by  side  plates  near  the  flange  angles  with  suf- 
ficient rivets  and  section  to  make  up  the  loss  in  the  moment  of 
inertia  of  the  girder  section  due  to  the  web  splice.    When  neces- 
sary to  splice  the  flange  angles  they  shall  break  joints  and  be 
spliced  by  angle  splices  in  pairs  on  both  sides  of  the  flange. 

Top  Lateral  Bracing  in  Deck  Girders. 

21.  The  top  lateral  bracing  of  deck  girders  shall  be  so  de- 
signed that  the  unsupported  length  of  the  flange  shall  not  be 
greater  than  12  times  its  width. 

Gusset  Plates  in  Half  Through  Girders. 

22.  The  cross  floor  beams  will  be  connected  to  the  main  gird- 
ers in  half  through  girder  bridges  with  gusset  plates  which  shall 
be  as  wide  as  the  standard  clearance  diagram  permits.     These 
gusset  plates  shall  be  fully  spliced  to  the  floor  beam  webs. 

Hinge  or  Spherical  Bearings. 

23.  Plate  girder  spans  over  75  feet  in  length  shall  be  provided 
with  pin  bearing  shoes  or  cast  steel  spherical  bearings  and  also 
with  expansion  rollers  at  one  end. 

y 

Bed  Plates  and  Anchor  Bolts. 

24.  Bed  plates  under  plate  girders  shall  not  be  less  than  J  of 
an  inch  thick  with  anchor  bolts  i^  inch  in  diameter  extending 
12  inches  into  the  masonry.     Where  two  spans  rest  on  an  inter- 
mediate pier,  the  masonry  plates  shall  be  continuous  under  both 
spans.     Deck  plate  girder  spans  not  over  75  feet  in  length  shall 


21 

be  riveted  up  complete  at  the  shops,  if  the  shipping  facilities  per- 
mit it,  unless  otherwise  directed  by  the  Chief  Engineer. 

Rounded  Ends. 

25.  The  upper  corners  of  half  through  plate  girders  shall  be 
neatly  rounded  to  a  radius  of  about  18  inches,  or  J  of  the  depth 
of  the  girder  for  girders  over  54  inches  deep.     The  first  flange 
plate  or  a  plate  of  the  same  width  will  be  bent  around  the  curve 
and  continued  to  the  bottom  of  the  girder.     In  a  bridge  consist- 
ing of  two  or  more  spans,  only  the  corners  on  the  extreme  ends 
need  be  rounded,  unless  the  spans  have  girders  of  varying  depths, 
in  which  case  the  deeper  ones  shall  have  their  top  flanges  neatly 
curved  down  to  meet  the  corner  of  the  girder  in  the  next  span. 

Viaducts  and  Trestles.  • 

26.  Each  trestle  tower  shall  in  general  consist  of  two  adjoin- 
ing bents,  each  of  which  latter  will  generally  consist  of  two  sup- 
porting columns.     The  columns  will  have  a  batter  transversely 
not  less  than  6  vertical  to  I  horizontal  for  single  track,  and  not 
less  than  8  vertical  to  I  horizontal  for  double  track.     All  towers 
shall  be  well  braced  transversely  to  resist  wind  pressure,  and,  if 
on  a  curve,  centrifugal  force ;  and  shall  be  braced  longitudinally 
to  resist  the  maximum  possible  stresses  due  to  traction  or  setting 
brakes.     They  shall  also  have  diagonal  lateral  bracing-  in  hori- 
zontal planes  in  each  story  and  at  the  feet,  and  shall  have  struts 
between  the  feet  of  the  columns  both  in  the  planes  of  the  bents 
and  of  the  sides  of  the  towers.    The  columns  shall  be  anchored  to 
the  pedestals  or  masonry  with  anchor  bolts  sufficient  to  resist 
double  the  calculated  stresses  that  may  come  upon  them.     The 
tower  spans  of  high  trestles  shall  not  be  less  than  30  feet  center 
to  center  of  bents  and  shall  alternate  with  free  spans  between  the 
towers  which  may  be  of  economic  length.     Both  the  tower  spans 
and  free  spans  will  generally  consist  of  plate  girders.    Foot  walks 
and  railings  shall  be  provided  when  required. 

Connections. 

27.  The   tower   girders   shall   be  riveted   between   transverse 
girders  which  in  turn  shall  be  riveted  between  the  columns.    The 


22 


free  girders  shall  be  riveted  to  the  transverse  girders  at  one  end 
and  shall  be  provided  with  expansion  joints  at  the  other  end. 


TRUSS    BRIDGES. 
Main  Features. 

28.  Preference  will  be  given  to  forms  of  trusses  avoiding  all 
ambiguity  in  stress  and  giving  the  greatest  rigidity.    Economy  in 
design  will  be  considered  wherever  possible  without  a  sacrifice  of 
simplicity,  rigidity  and  durability.     Adjustable  members  in  any 
part  of  the  structure  shall  preferably  be  avoided.     Counter  brac- 
ing will  be  preferred  to  the  use  of  counter  members.     All  parts 
shall  be   so  designed  that  they  can  be   inspected,   cleaned  and 
painted.    Closed  sections  will  not  be  permitted.    Eccentric  stresses 
will  not  be  permitted  where  avoidable,  and  when  they  occur  the 
sections  shall  be  increased  to  meet  these  stresses  without  exceed- 
ing the  allowed  unit  stresses.     The  width  center  to  center  of 
trusses  shall  generally  not  be  less  than  one-twelfth  of  the  span 
apd  in  no  case  less  than  one-twentieth  of  the  span. 

Riveted  Trusses. 

29.  The  upper  chords  and  end  posts  shall  generally  be  made  of 
two  side  segments  with  one  cover  plate  and  with  tie  plates  and 
latticing  on  the  bottom  flanges.     Gusset  plates  connecting  the  va- 
rious members  shall  have  a  thickness  proportionate  to  the  amount 
of  stress  they  have  to  transfer.    The  ends  of  riveted  trusses  shall 
be  provided  with  pin  bearings  and  bolsters  with  provisions  for 
expansion  at  one  end.     Masonry  plates  shall  not  be  less  than  one 
inch  thick,  and  where  two  spans  join  one  another  on  the  same 
pier  they  shall  extend  continuously  under  the  shoes  of  both  spans. 

Pin  Connected  Trusses. 

30.  Pin  connected   trusses  will   generally  have   inclined   end 
posts,   and   the   bottom   chords   and   suspenders   in   the   two   end 
panels  at  each  end  shall  be  stiff  riveted  members.     All  suspenders 
in  through  spans  shall  generally  be  stiff  riveted  members. 


23 

MOVABLE    BRIDGES. 

Swing  Bridges. 

31.  Swing  bridges  shall  be  calculated  for  the  following  con- 
ditions : 

I.     Dead  load,  bridge  swinging. 
II.     Dead  load,  bridge  closed,  ends  lifted  as  per  paragraph  34. 

III.  Live  load  in  any  position  on  one  arm,  considered  as  a 
simple  span  over  two  supports. 

IV.  Live  load  in  any  position  on  one  arm  only,  considered  as 
a  continuous  span. 

V.     Live  load  on  both  arms,  considered  as  a  continuous  span. 
To  obtain  the  maximum  and  minimum  stresses  to  be  used  in 
proportioning  the  members,  combine  condition  I  with  III  and  V, 
or  II  with  IV  and  V. 

Turn  Tables. 

32.  Turn  tables  for  swing  bridges  will  be  so  designed  as  to 
avoid  ambiguity,  and  to  distribute  the  loads  equally  and  symmetri- 
cally on  the  masonry. 

Machinery. 

33.  When  machinery  for  operating  by  power  is  required,  it  will 
be  specified,  but  hand  apparatus  will  be  furnished  whether  or  not 
the  bridge  is  equipped  with  steam,  electric  or  other  power.     The 
time  required  for  opening  and  closing  will  be  determined  by  the 
Chief  Engineer,  and  the  contractor  will  be  responsible  for  the  pro- 
portions of  the  machinery  to  meet  this  requirement. 

The  design  and  quality  of  material  and  workmanship  used  in 
all  operating  machinery,  wedges,  jacks,  toggles  or  cams,  latches, 
rail  lifts,  signals,  indicators,  etc.,  shall  be  subject  to  the  approval 
of  the  Chief  Engineer. 

All  motions  shall  be  controlled  from  one  Cabin,  so  located  as  to 
afford  the  operator  an  unobstructed  view  of  the  entire  bridge 
and  approaches.  Provision  shall  be  made  in  the  Cabin  for  an 
interlocking  signal  machine. 

Indicators  shall  be  placed  in  the  Cabin  to  show  accurately  the 


24 

position  of  all  lifts  and  latches.  All  bolts  in  machinery  shall  be 
turned  and  have  heads  and  nuts  faced  and  be  provided  with 
check  nuts.  All  bearings  shall  have  oil  holes  and  ducts,  and  oil 
cups  when  required.  All  shaft  bearings  will  be  provided  with 
compression  grease  cups.  Thes-e  shall  be  so  located  as  to  be  as 
accessible  as  possible. 

Lifts  and  Latches. 

34.  When  the  bridge  is  closed,  a  sufficient  amount  of  dead 
load  must  be  carried  by  the  rest  piers  to  prevent  hammering  un- 
der live  load.     This  will  generally  be  accomplished  by  end  lifts, 
but  may  be  effected  by  mechanism  controlling  the  length  of  the 
center  panel  of  the  top  chord.     Efficient  rail  lifts  and  latches  shall 
be  provided,  satisfactory  to  the  Chief  Engineer.     The  rails  shall 
have  beveled  ends  and  be  provided  with  shoes,  guides,  bridles, 
etc.     These  shall  all  be  furnished  by  the  contractor  for  the  steel 
superstructure  and  machinery,  and  shall  include  all  special  rails, 
but  not  the  straight  track  rails.    The  section  of  special  rails  shall 
be  that  adopted  by  the  Railroad  Company  as  its  standard,  and 
shall  conform  to  the  Railroad  Company's  Specifications  for  steel 
rails. 

Cabin  and  Signal  Lights. 

35.  An  operator's  cabin  shall  be  provided,  and  shall  be  attrac- 
tive in  design,  substantial  in  construction,  and  located  as  directed 
by  the  Chief  Engineer.     Iron  ladders  or  stairs  shall  be  furnished 
connecting  the  floor  of  the  bridge  with  the  center  pier  and  with 
the  cabin.     The  contractor  shall  furnish  and  set  all  signal  lights 
required. 


III. 

LOADS. 

All  structures  shall  be  proportioned  to  carry  the  following 
loads : 

36.  A   dead  load,  consisting  of  the  weight  of  the  structure 
complete,  including  the  floor,  tracks,  etc.    The  weight  of  the  rails 
and  fastenings  will  be  assumed  at  100  pounds  per  lineal  foot  of 
track,  the  weight  of  timber  at  4-^-  pounds  per  foot  B.  M.,  and  the 
weight  of  ballast  at  no  pounds  per  cubic  foot,  but  the  combined 
weight  of  the  rails,  ties  and  guard  rails  shall  never  be  taken  at 
less  than  400  pounds  per  lineal  foot  of  track.    The  dead  load  will 
be  assumed  to  be  concentrated,   f  on  the  loaded  chord  and  J  on 
the  unloaded  chord. 

37.  A  live  load,  consisting  of  two  consolidation  engines  fol- 
lowed by  a  uniform  train  load,  which,  unless  otherwise  specified, 
shall  be  according  to  the  weights  and  spacing  shown  on  the  dia- 
gram entitled  "Typical  Loading"  attached  hereto;  or  a  concen- 
trated loading  of  120,000  pounds  on  two  axles  spaced  6  feet  cen- 
ter to  center.     This  is  the  £-50  loading  of  the  Cooper  Series. 

If  heavier  or  lighter  loadings  are  desired,  they  will  be  speci- 
fied in  the  letter  of  invitation  and  will  be  designated  by  the  index 
numbers,  as  £-40,  £-45,  £-55,  E-6o,  etc.,  and  they  shall  be  pro- 
portional to  the  E-5O  loading,  specified  above  and  shown  on 
diagram,  with  the  same  wheel  base. 

Unless  otherwise  directed  by  the  Chief  Engineer,  the  following 
uniform  live  loads  per  lineal  foot  of  track  may  be  substituted  for 
the  typical  train  loadings  above  specified: 

A  live  load,  per  lineal  foot  of  track,  of  ;'T"  divided  by  (the 
cube  root  of  the  length  of  the  span  in  feet  plus  the  sixth  root  of 
the  length  of  the  span  in  feet).  The  values  of  "T,"  approxi- 
mately corresponding  to  the  loadings  of  the  "E"  Series,  are  as 
follows : 


26 


T=4°>oo°  f( 

)r  £-40  loading. 

T=45,ooo    " 

:     E-45 

T=5o,ooo   " 

E-SO 

T=55,ooo   " 

E-55        " 

T=6o,ooo   " 

E-6o 

The  table  hereto  attached  gives  the  load  per  foot  of  track  for 
"T"=5o,ooo  for  spans  of  10  feet  to  500  feet.  For  "T"  equal  to 
any  other  value,  the  load  per  foot  of  track  will  be  proportional. 

The  value  of  "T,"  or  the  index  of  the  loading  by  this  series,  is 
approximately  equal  to  the  weight  on  each  driving  axle  in  pounds, 
or  ten  (10)  times  the  following  load  per  lineal  foot  of  track. 

These  loads  shall  be  so  placed  as  to  produce  the  greatest  stress 
in  each  member.  Wherever  the  live  and  dead  load  stresses  are 
of  opposite  character,  only  70  per  cent,  of  the  dead  load  stress 
shall  be  considered  as  effective  in  counteracting  the  live  load 
stress. 

38.  An  allowance  for  impact  or  dynamic  effect  of  live  loads, 
when  there  is  no  reversal  of  stress,  eq'ual  to  the  live  load  multiplied 
by  the  maximum  stress,  divided  by  the  maximum  stress  plus  the 
minimum  stress  in  the  member  considered.     When  a  member  is 
subject  to  reversal  of  stress,  this  allowance  (to  be  applied  to  the 
live  load  stress  of  each  kind)  shall  be  equal  to  that  live  load  mul- 
tiplied by  I  plus  twice  (the  maximum  stress  of  lesser  kind  divided 
by  the  maximum  stress  of  greater  kind).    The  stresses  due  to  the 
loads  specified  in  paragraphs  36  and  37,  only,  shall  be  used  in 
calculating  the  above  allowances. 

Stresses  due  to  momentum,  or  tractive  force  of  engines  and 
stresses  due  to  centirfugal  force,  will  be  increased  by  an  amount 
to  provide  for  impact  or  dynamic  effect  one-half  the  amount 
provided  for  above,  and  shall  be  treated  as  distinct  from  the 
impact  added  to  live  load  stress. 

For  members  in  which  the  maximum  stresses  are  produced  by 
loads  on  two  or  more  tracks,  the  above  allowances  shall  be  re- 
duced by  twenty  (20%)  per  cent. 

39.  An  allowance  for  wind  loads  and  lateral  vibration,  as  fol- 
lows : 


27 

Dead  Load,  150  pounds  per  lineal  foot  on  the  unloaded  chord, 
and  200  pounds  per  lineal  foot  on  the  loaded  chord. 

Moving  Load,  400  pounds  per  lineal  foot  on  the  loaded  chord, 
applied  at  a  distance  of  six  feet  above  the  base  of  rail. 

In  calculating  the  righting  moment  for  wind  reactions,  the 
weight  of  the  train  will  be  assumed  at  800  pounds  per  lineal  foot. 
In  trestle  towers  the  bracing  and  columns  shall  be  proportioned 
to  resist  the  above  specified  wind  loads  and  in  addition  a  hori- 
zontal load  of  180  pounds  for  each  vertical  foot  of  bent.  In  cal- 
culating wind  stresses  in  trestle  bents  carrying  double  track,  the 
conditions  ,with  or  without  loads  on  either  one  or  both  tracks,  and 
with  the  maximum  train  load  and  with  a  train  load  of  800  pounds 
per  lineal  foot,  shall  be  considered  and  the  maximum  stresses  pro- 
duced by  either  condition  shall  be  used. 

Centrifugal  Force. 

40.  When  the  structure  is  located  on  a  curve,  a  centrifugal 
force  acting  5  feet  above  the  base  of  rail  and  treated  as  live  load 
shall  be  computed  by  the  following  formula  for  a  maximum  train 
on  each  track  moving  at  a  speed  of  60 — 3D  miles  per  hour,  D 

being  the  degree  of  curvature.  C=  ™ r  >  m  which  C=centrif- 
ugal  force,  w=weight,  v=velocity  in  feet  per  second  and  r= 
radius  of  curve. 

Traction  and  Momentum. 

41.  The  stresses  produced  in  the  longitudinal  bracing  of  tres- 
tle towers  or  in  any  members  or  parts  of  girders  or  trusses  or 
any  of  their  attachments  or  bearings  by  the  greatest  tractive  force 
of  the  engines  or  by  the  sudden  stopping  of  trains  on  any  part 
of  the  structure  must  be  provided  for.     In  all  structures,  provi- 
sion must  be  made  for  trains  going  in  either  direction  and  on  any 
track.     In  determining  the   reaction  and  uplift  on  the  base  of 
tower  legs,  when  traction  and  momentum  are  considered  in  com- 
bination with  wind  and  centrifugal  force,  the  amount  of  the  for- 
mer shall  be  taken  at  one-half  of  that  above  specified. 
Thermal  Forces. 

42.  Where  designs  do  not  permit  of  free  expansion  and  con- 
traction due  to  changes  in  temperature  of  150  degrees,  thermal 
stresses  must  be  provided  for. 


IV. 
WORKING    STRESSES.' 

The  following  maximum  permissible  unit  stresses  shall  not  be 
exceeded  in  any  member  or  part  of  a  structure : 

Tension. 

43.  Axial  tension  on  net  section,   16,000  pounds  per  square 
inch.     For  floor  beam  hangers  and  suspenders  subject  to  sudden 
loading,  12,000  pounds  per  square  inch. 

Compression. 

44.  Axial     compression     on     gross     section,     16,000 — 800 

pounds  per  square  inch  ; —  r 

Where  L=the  length  of  the  member  in  feet,  and  r=the  least 
radius  of  gyration  in  inches. 

L 

The  ratio  of--  shall  never  be  greater  than  8J  for  main  mem- 
r 

bers,  nor  greater  than  10  for  struts  and  bracing  subject  to  stress 
from  live  or  wind  loads,  but  not  including-  struts  in  viaduct  tow- 
ers, and  not  greater  than  12  for  struts  and  bracing  subject  to 
stress  from  dead  load  only  or  for  struts  in  viaduct  towers.  The 
least  width  of  posts  in  pin  connected  bridges  shall  be  limited  to 
ten  (10)  inches,  for  all  members  subject  to  stress  from  live  loads. 

Combined  Stresses. 

45.  A  member  subject  to  transverse  stress  in  addition  to  the 
tension  or  compression  due  to  its  position  shall  be  considered  as 
a  beam  of  one  panel  length  supported  at  the  ends  for  section  in 
center  of  panel  and  fixed  at  the  ends  for  section  at  the  ends  of 
panel.     The  members  will  be  proportioned  to  sustain  the  alge- 
braic sum  of  the  stresses  resulting  from  the  direct  compression 


29 

or  tension  and  the  transverse  loading,  so  that  the  allowed  stress 
per  square  inch  shall  not  exceed  those  given  above. 

NOTE. — For  top  chords,  the  stresses  per  square  inch  due  to 
weight  of  member  will  be  deducted  from  the  above  unit  stresses. 

If  the  length  of  panel  divided  by  the  least  radius  of  gyration  of 
the  top  chord  is  less  than  the  length  of  span  divided  by  the  radius 
of  gyration  of  the  top  chords,  considered  as  a  trussed  column, 
the  latter  will  be  used  in  finding  the  area  of  top  chord  sections. 

46.  No  allowance  will  be  made  for  wind  stress  when  com- 
bined with  stress  from  dead  and  live  load  and  impact,  unless  the 
wind  stress  exceeds  the  amount  of  stress  allowed  for  impact  or 
dynamic  effect,  in  which  case  the  excess  of  the  wind  stress  over 
and  above  that  allowed  for  impact  or  dynamic  effect  shall  be 
added  to  the  sum  of  the  other  stresses  to  give  the  maximum  stress 
to  be  used  in  proportioning  the  section. 

Shearing. 

47.  On    pins    and    rivets,    12,000    pounds    per    square    inch. 

d 
On   webs    of   girders   and   beams,    16,000 — 100  -  -  pounds   per 

square  inch,  in  which  d=the  clear  distance  between  flange  angles 
or  stiffener  angles,  and  t=the  thickness  of  the  web,  both  in  inches. 

Stiffeners. 

48.  All  web  plates  shall  be  stiffened  at  the  inner  edges  of  end 
bearing,  and  at  all  points  of  local  concentrated  loadings.     Inter- 
mediate stiffeners  will  be  used  where  required,  so  that  the  shear- 
ing- stress  per  square  inch  shall  not  exceed  that  given  by  the  for- 
mula of  the  preceding  paragraph. 

Bearing. 

49.  On  the  projected  semi-intrados  of  pin  and  rivet  holes, 
24,000  pounds  per  square  inch. 

On  masonry,  400  pounds  per  square  inch. 

Bending. 

50.  On  extreme  fiber  of  rivets  and    pins,  24,000  pounds  per 
square  inch. 


30 

51.  For  rivets  driven  in  the  field,  except  in  lateral,  sway  and 
longitudinal  bracing,  the  above  unit  stresses  shall  be  reduced  20 
per  cent. 

For  shop  driven  rivets  in  lateral,  sway  and  longitudinal  brac- 
ing, the  above  unit  stresses  may  be  increased  20  per  cent. 

Timber. 

52.  Stress  in  extreme  fibers  under  transverse  loading,  with 
no  allowance   for   impact  or  dynamic   effect,    1,200   pounds   per 
square  inch  for  yellow  pine,  white  oak  and  Oregon  or  Douglas 
fir,  and  1,000  pounds  per  square  inch  for  pine  and  other  timbers. 

Compression,  in  posts  or  struts,  with  no  allowance  for  impact  or 

dynamic  effect,  860 — no  -r-  pounds  per  square  inch  for  yellow 
pine,  white  oak  and  Oregon  or  Douglas  fir,  and  750 — 100  -7- 

pounds  per  square  inch  for  pine  and  other  timbers. 

Where  L=the  length  of  the  member  in  feet  and  d=the  least 
dimension  of  the  member  in  inches. 


Shearing. 

Sliding  on  the  grain,  100  pounds  per  square  inch. 

Bearing. 

Direction  of  the  grain,  1,000  pounds  per  square  inch. 
Perpendicular  to  the  grain,  300  pounds  per  square  inch. 


Unit  Stress  for  Momentum  and  Centrifugal  Force. 

53.  Stresses  due  to  momentum,  or  tractive  force  of  engines, 
and  stresses  due  to  centrifugal  force  will  be  increased  by  an 
amount  to  provide  for  impact,  as  specified  in  paragraphs  38,  for 
which  purpose  the  sum  of  all  the  stresses,  when  there  is  more 
than  one,  will  be  taken  as  the  maximum  and  the  smaller  of  them 
that  can  act  separately  as  the  minimum. 


31 

Friction. 

54.     The  coefficients  of  friction  will  be  assumed  as  follows: 


.5  55  o> 
o  g  « 

CJ    U-    ?•> 


rt  u  Si 


For  wheels  sliding  on  steel  rails 

For  plane  surfaces  of  steel  or  cast  iron 

For  plane  surfaces  of  wood  on  metal 

For  steel  rollers  between  plane  surfaces  of  steel... 


0.25 
&  •  30 
0.50 
0.05 


0.15 
0.15 
0.25 

O.OOI 


Bearing  on  Rollers  and  Wheels. 


in 


55.  The  pressure  per  lineal  inch  on  rollers  and  wheels 
pounds  shall  not  exceed,  for  expansion  rollers,  600  D. 

For  steel  wheels  of  swing  bridge  turn  tables,  on  steel  tracks, 
600  D. 

Cast  iron  wheels  will  not  be  used. 

Where  D=diameter  of  roller  or  wheel  in  inches. 

Transverse  Loading. 

56.  All  beams  or  girders,  rolled  or  built,  shall  be  proportioned 
by  the  least  moment  of  inertia  of  their  net  section,  and  compres- 
sion flanges  shall  have  the  same  gross  area  as  tension  flanges. 


V. 
GENERAL    DETAILS. 

Unsymmetrical  Sections. 

57.  Unsymmetrical  sections  composed  of  two  rolled  or  built 
channels  and  one  plate  shall,  in  chords,  be  so  proportioned  that 

'the  centers  of  pins  in  abutting  members  shall  be  in  the  same  line 
and  in  the  center  of  gravity  of  the  section;.  In  web  members  ec- 
centricity may  be  made  sufficient  to  counteract  the  bending 
stress  due  to  weight  of  members  under  maximum  load.  The 
material  will  be  concentrated  mostly  in  the  channels. 

H-Sections. 

58.  H-shaped  sections  composed  of  three  channels  or  four 
Z-bars,  if  exceeding  ten  inches  in  depth,  shall  have  tie  plates  at 
ends  holding  them  truly  square. 

Tension  Members. 

59.  Tension  members  in  riveted  trusses  shall  be  symmetrical 
and  attached  to  both  webs  of  the  chords.     Riveted  trusses  with 
single  web  chords  will  not  be  used.     All  parts  working  together 
or  parts  of  one  member  of  the  truss  must  be  so  designed  that  each 
part  will  take  its  proper  proportion  of  stress. 

Floor  Beam  Connection. 

60.  In  through  bridges  the  floor  beams  will    preferably  be 
above  the  bottom  chord.    Vertical  posts  and  stiff  suspenders  will 
preferably  be  composed   of   four   Z-bars  or   angles,   latticed,   to 
which  the  floor  beams  will  be  riveted  with  rivets  in  double  shear. 

Bracing. 

61.  All  lateral,  sway  and  longitudinal  bracing  shall  be  made 
of  stiff  riveted  members.  They  shall  be  so  connected  to  the  trusses 
as  to  give  the  minimum  amount  of  bending  or  eccentric  stresses. 


33 

Lateral  Bracing. 

62.  All  bridges,  wherever  practicable,  when  over  50  feet  in 
length,  shall  have  both  top  and  bottom  lateral  bracing. 

Top  Lateral  Struts. 

63.  Top  lateral  struts  will  have  a  depth  equal  to  the  depth  of 
the  chord  and  be  securely  riveted  thereto. 

Sway  Bracing. 

64.  All  deck  bridges  and  through  bridges  having  a  depth  of 
30  feet,  or  over,  shall  have  sway  bracing  at  each  panel  point. 
Through  bridges  less  than  30  feet  in  depth  shall  have  knee  braces 
between  each  intermediate  post  and  top  strut.     Knee  braces  or 
brackets  will  also  be  required  between  each  post  and  sub-strut  in 
through  bridges  over  30  feet  in  depth,  and  at  all  portals. 

Portals. 

65.  All  through  bridges  shall  have  portal  bracing  of  approved 
design  between  the  end  posts  at  each  end.    For  spans  of  200  feet 
and  under,  each  portal  will  consist  of  four  angles  riveted  to  the 
end  posts  and  connected  by  diagonal  lacing.     The  lacing  will  be 
flat  bars  if  the  depth  of  portal  does  not  exceed  three  feet,  and 
angles  if  of  greater  depth. 

For  spans  exceeding  200  feet  in  length,  the  portals  may  con- 
sist of  top  and  bottom  struts  connected  by  cross  bracing. 

Parallel  Deck  Spans. 

66.  Horizontal  struts  shall  be  used  to  connect  each  panel  point 
of  the  top  chord  of  parallel  deck  spans. 

Cross  Frames. 

67.  Cross  frames  shall  be  used  at  each  end  of  deck  plate  girder 
spans,  and  intermediate  cross  frames  at  intervals  of  about  20  feet 
where  top  and  bottom  lateral  bracing  is  used,  or  at  intervals  of 
about  12  feet  where  only  top  lateral  bracing  is  used. 


34 

Stringer  Bracing. 

68.  Track  stringers  shall  be  provided  with  a  top  lateral  sys- 
tem when  the  span  exceeds  12  times  the  width  of  the  top  flange 
and,  in  addition,  shall  have  cross  frames  when  the  span  exceeds 
30  feet.  - 

Sections  and  Connection  of  Bracing. 

69.  Braces  that  take  compression,  except  in  deck  plate  girder 
spans,  shall  generally  be  built  of  four  angles  or  two  channels. 
Braces  that  take  tension  only  may  consist  of  one  angle,  which 
shall  not  be  less  than  4  inches  by  3  inches  by  f  inch,  except  for 
stringer  braces,  which  may  be  3  inches  by  3  inches  by  f  inch. 
Ail  connections  of  braces  shall  have  a  sufficient  number  of  rivets 
to  develop  the  full  strength  of  the  brace,  but  in  no  case  will  they 
be  connected  by  less  than  four  rivets  for  main  braces  or  three 
rivets  for  stringer  bracing.     Braces  consisting  of  a  single  angle 
shall  have  both  legs  of  the  angle  connected  or  only  one  leg  will 
be  considered  as  effective.   All  intersecting  braces  shall  be  riveted 
together. 

Minimum  Sections. 

70.  No  metal  shall  be  less  than  f  inch  thick,  except  fillers  and 
webs  of  rolled  channels,  which  latter  shall  not  be  less  than  5-16 
inch  thick.     No  angles  shall  be  used  less  than  3^x3jxf  inches, 
except  for  stringer  laterals  and  minor  details,  which  may  be  3x 
3xf  inches. 

Pins,  Pin  Plates  and  Eye  Bars. 

71.  The   diameter   of   the   pins   shall   never   be   less   than   J 
of  the  width  of  the  largest  eye  bars   which  they  connect,  and 
the  axis  of  all  pins  must  be  on  the  center  of  gravity  of  all  mem- 
bers connected.     The  form  of  heads  and  method  of  manufacture 
of  eye  bars  shall  be  subject  to  the  approval  of  the  Chief  Engineer. 
Eye  bars  shall  be  so  arranged  or  packed  as  to  produce  the  mini- 
mum bending  moment  in  the  pins.     They  shall  not  be  more  than 
one-eighth  of  an  inch  in  one  foot  out  of  parallel  with  the  center 
line  of  truss.     Pin  plates  shall  be  used  to  give  the  required  bear- 
ing surface  on  the  pins,  and  shall  have  sufficient  rivets  to  properly 


35 

distribute,  without  eccentricity,  the  proportion  of  the  stress  which 
they  carry.  In  built  tension  members  the  section  through  pin 
holes  shall  be  25  per  cent,  in  excess  of  the  net  section  of  the  body 
of  the  member.  The  net  section  back  of  the  pin  hole  shall  be  at 
least  0.75  of  the  net  section  through  the  pin  hole.  Where  the  sec- 
tion at  the  ends  of  compression  members  has  been  reduced  by  cut- 
ting the  flanges,  or  in  any  other  way,  the  pin  plates  shall  have 
enough  rivets  beyond  the  reduced  portion,  and  shall  have  sufficient 
section  to  make  up  the  equivalent  of  the  metal  cut  away. 

Shoes,  Bed  Plates  and  Rollers. 

72.  The  shoes  or  bolsters  shall  be  so  designed  that  all  loads 
will  act  through  the  end  pins,  which  will  be  directly  over  the 
geometrical  center  of  the  bearing,  and  to  properly  distribute  these 
loads.     Where  the  necessary  height  between  masonry  and  center 
of  end  pins  can  be  obtained,  masonry  or  bed  plates  built  up  of 
beam  sections  will  be  preferred.    They  shall  be  securely  anchored, 
with  bolts  set  in  cement,  which  shall  not  be  less  than  ij  inches 
in  diameter,  nor  extend  less  than  12  inches  into  the  masonry;  pro- 
vision being  made  for  expansion.    Where  the  masonry  is  of  con- 
crete, grillages  of  steel  I-beams  will  be  embedded  in  the  concrete, 
flush  with  the  surface,  to  form  the  bridge  seat,  for  all  spans  ex- 
ceeding one  hundred  feet  in  length.    The  contractor  for  the  super- 
structure shall  furnish  these  grillages  as  a  part  of  his  contract 
and  shall  deliver  them  at  the  earliest  possible  date  and  in  advance 
of  the  delivery  of  the  steel  for  the  superstructure. 

Effective  Diameter  of  Rivets. 

73.  The  effective  diameter  of  the  driven  rivet  will  be  assumed 
the  same  as  its  diameter  before  driving,  but  in  making  deductions 
for  rivet  holes  in  tension  members  the  diameter  of  the  holes  will 
be  assumed  J  inch  larger  than  the  undriven  rivet. 

Pitch  of  Rivets. 

74.  The  pitch  of  the  rivets  shall  not  exceed  6  inches,  nor  be 
less  than  three  diameters  of  the  rivet,  where  there  is  only  one 
gauge  line,  nor  exceed  nine  inches  where  there  are  two  or  more 


36 

gauge  lines.  At  the  ends  of  compression  members,  the  pitch  shall 
not  exceed  four  diameters  of  the  rivet  for  a  length  equal  to  twice 
the  depth  of  the  member,  and  in  the  flanges  of  girders  and  chords 
carrying  floor  the  pitch  shall  not  exceed  4  inches  where  there  is 
only  one  gauge  line,  nor  8  inches  where  there  are  two  or  more 
gauge  lines.  In  compression  members  the  pitch  in  the  direction 
of  the  stress  shall  not  exceed  16  times  the  thickness  of  the  outside 
plate.  Transversely  to  the  line  of  stress  it  shall  not  exceed  32 
times  that  thickness,  except  for  the  cover  plates  of  trough  sec- 
tions, where  it  shall  not  exceed  40  times  the  thickness  of  the 
plate. 

Distance  from  Center  of  Rivet  to  Edge  of  Plate. 

75.  The  distance  from  center  of  rivet  to  edge  of  plate  shall 
not  be  less  than  i^  inches,  except  in  bars  under  3  inches  wide. 
When  practicable,  it  shall  be  at  least  two  diameters  of  the  rivet. 
It  shall  not  exceed  eight  times  the  thickness  of  plate. 

Grip  of  Rivets. 

76.  The  grip  of  the  rivets,  or  the  total  thickness  of  all  the 
pieces  connected,  shall  not  be  more  than  five  times  the  nomin?.! 
diameter  of  the  rivet. 

Tie  Plates  and  Lacing. 

77.  The  open  sides  of  all  members  composed  of  rolled  or  built 
channels,  or  similar  sections,  and  the  center  of  members  com- 
posed of  four  angles  or  Z-bars,  without  a  web  plate,  shall  be 
stayed  by  tie  plates  at  the  ends  and  at  points  of  intersection  with 
other  members,  and  by  diagonal  lacing  or  lattice  bars  forming  a 
continuous  triangulation  between  the  tie  plates. 

Length  of  Tie  Plates. 

78.  The  length  of  tie  plates  at  the  ends  of  members  shall  be 
«qual  to  the  greatest  width   of  the  member.     Intermediate  tie 
plates  shall  have  a  length  at  least  equal  to  one-half  the  greatest 
width  of  the  member. 


37 
Double  Lattice. 

79.  Compression  members  having  a  greater  clear  width  than 
12  inches  between  the  segments  shall  be  double  latticed.  All  other 
members  may  be  single  laced.  Double  lattice  bars  shall  form  an 
angle  with  the  axis  of  the  member  not  less  than  45  degrees,  shall 
be  riveted  at  their  intersection  and  have  a  thickness  not  less  than 
f  of  an  inch  nor  less  than  1-60  of  the  distance  between  the  rivets 
connecting  them  to  the  members. 

Single  Lacing.    . 

So.  Single  lacing  bars  shall  form  an  angle  of  not  less  than  60 
degrees  with  the  axis  of  the  member,  and  have  a  thickness  not 
less  than  f  of  an  inch  nor  less  than  1-40  of  the  distance  between 
the  rivets  connecting  them  to  the  members. 

Width  and  Spacing  of  Bars. 

81.  No  lattice  or  lacing  bar  shall  be  less  in  width  than  2\ 
inches,  nor  less  than  3  diameters  of  the  rivets.     The  spacing  be- 
tween connections  of  the  bars/  shall  not  exceed  six  times  the  least 
width  of  the  segments  connected. 

Bolts. 

82.  All  bolts  must  be  of  neat  length  and  have  a  washer  under 
head  and  nut  when  they  are  in  contact  with  wood. 

Washers  and  Nuts. 

83.  Washers  and  nuts  shall  have  a  uniform  bearing.     All 
nuts  shall  be  easily  accessible  with  a  wrench,  for  the  purpose  of 
adjustment,  and  shall  be  effectively  checked  after  the  final  ad- 
justment.   All  nuts  must  be  of  hexagonal  shape,  except  those  on 
guard  rail  bolts  and  hook  bolts  in  floors,  which  shall  be  square. 

Drainage. 

84.  Wherever  there  is  a  tendency  for  water  to  collect,  the 
spaces  must  be  drained  or  filled  with  waterproof  material. 


33 

Turn  Tables  of  Swing  Spans. 

85.  The   drum   shall   be   of    sufficient   strength   to  carry   all 
weights  which  come  on  it  to  the  adjoining  wheels,  in  case  the 
wheel  immediately  under  the  point  of  support  is  not  bearing.   The 
wheels  of  the  table  must  be  faced  to  exact  size  and  bevel.     The 
upper  and  lower  tracks  must  be  planed  or  faced  to  the  true  bevel, 
and  must  have  a  face  three-fourths  of  an  inch  wider  than  the 
tread  of  the  wheels.     Provisions  for  lubrication  shall  be  made  so 
as  to  be  easily  accessible.     The  arrangements  shall  be  such  that 
the  bearing  wheels  or  the  center  pins  can  be  readily .  removed  if 
out  of  order.    The  rack,  track  and  center  pedestal  shall  be  accu- 
rately bolted  to  the  masonry,  and  in  such  a  manner  as  will  easily 
permit  of  adjustment.    The  design  and  details  for  the  turn  table 
shall  be  subject  to  the  approval  of  the  Chief  Engineer.     The 
operating  machinery  shall  be  the  best  of  its  kind  and  complete  in 
every  particular,  including  small  tools  and  wrenches  for  all  bolts, 
oil  cans,  and  necessary  furnishings.     The  cabin  shall  be  ceiled 
inside  with  matched  and  beaded  ceiling,   furnished  with  neces- 
sary doors,   windows  and  hardware,  and  covered  outside  with 
galvanized  corrugated  iron  No.  22.     The  roof  shall  be  covered 
with  best  roofing  tin  on  sheeting  and  furnished  with  gutters  and 
down-spouts  of  No.  22  galvanized  iron.  All  gearing  and  important 
castings  shall  be  of  steel.     Extra  or  duplicate  parts  shall  be  fur- 
nished for  gearing  and  other  details,  a  list  for  which  shall  be 
submitted  to  the  Chief  Engineer,  with  the  detail  or  shop  plans,  for 
his  approval, 

Camber. 

86.  Fixed  trusses  shall  be  given  a  cambei  by  increasing  the 
length  of  the  top  chord  by  one  one-thousandth   of  its   length. 
Swing  spans  shall  be  cambered  an  amount  equal  to  the  maximum 
calculated  deflection.     Plate  girders  shall  be  given  a  slight  cam- 
ber by  proper  manipulation  in  riveting,  so  that  they  will  not  have 
any  sag  when  erected  in  place. 

Expansion. 

87.  To  provide  for  expansion  and  contraction,  one  end  of  all 
spans  must  be  free  to  move  £  of  an  inch  for  each  ten  feet  of  length 


39 

and  shall  be  provided  with  expansion  rollers  or  the  equivalent 
.when  the  length  of  the  span  exceeds  75  feet.  The  diameter  of 
the  rollers  shall  not  be  less  than  three  inches  for  spans  of  75  feet, 
nor  less  than  six  inches  for  spans  of  200  feet,  and  proportional 
for  other  spans. 


OF  THE 

UNIVERSITY   ) 


VI. 
QUALITY   OF    MATERIAL. 

Kind  of  Steel  and  Chemical  Limitation. 

88.  All  steel  for  bridges  and  structures  shall  be  made  by  the 
open-hearth  process  and  shall  not  contain  more  than  .05  per  cent, 
sulphur.    The  phosphorus  shall  not  exceed  .08  per  cent,  in  acid 
steel  nor  .04  per  cent,  in  basic  steel. 

Grades  of  Steel. 

89.  Excepting  for  rivets,  which  shall  be  made  of  rivet  steel, 
and  excepting  for  eye  bars,  pins  and  rollers,  which  may  be  made 
of  medium  steel,  only  one  grade  of  steel  will  be  permitted  in  the 
work,  and  this  will  be  designated  as  structural  steel.  - 

Tensile  Strength  and  Elongation. 

90.  Wherever  the  term  structural  steel  is  used,  it  will  be  un- 
derstood to  mean  steel  having  the  following  properties : 

An  ultimate  tensile  strength  of  not  less  than  58,000  pounds 
nor  more  than  66,000  pounds  per  square  inch,  with  an  elongation 
of  at  least  25  per  cent,  in  eight  inches. 

Medium  steel  shall  have  an  ultimate  tensile  strength  of  not  less 
than  62,000  pounds  nor  more  than  70,000  pounds  per  square  inch, 
with  an  elongation  of  at  least  22  per  cent,  in  eight  inches. 

Rivet  steel  shall  have  an  ultimate  tensile  strength  of  not  less 
than  48,000  pounds,  nor  more  than  56,000  pounds  per  square  inch, 
with  an  elongation  of  at  least  26  per  cent,  in  eight  inches. 

The  Yield  Point. 

91.  For  all  grades  of  steel  the  yield  point,  as  determined  by 
the  careful  observation  of  the  drop  of  the  beam  or  halt  in  the 
gauge  of  the  testing  machine,  shall  be  not  less  than  55  per  cent, 
of  the  ultimate  tensile  strength  of  the  specimen. 


UNIVERSITY 


The  speed  of  the  testing  machine  shall  be  so  regulated  that 
these  determinations  can  be  made  accurately  and  uniformly,  and 
to  the  satisfaction  of  the  Chief  Engineer  or  his  inspectors. 

Modifications  of  Requirements  for  Elongation. 

92.  For  material  less  than  five-sixteenths  inch    (5-16  inch) 
and  more  than  three-fourths  inch  (J  inch)  in  thickness,  the  fol- 
lowing modifications  shall  be  made  in  the  requirements  for  elon- 
gation : 

(a).  For  each  increase  of  one-eighth  inch  (J  inch)  in  thick- 
ness above  three-fourths  inch  (J  inch),  a  deduction  of  one  per 
cent.  (  i  per  cent.  )  shall  be  made  from  the  specified  elongation. 

(b).  For  each  decrease  of  one-sixteenth  inch  (1-16  inch)  in 
thickness  below  five-sixteenths  inch  (5-16  inch)  a  deduction  of 
two  and  one-half  per  cent.  (2%  per  cent.)  shall  be  made  from  the 
specified  elongation. 

(c.)  For  pins  made  from  any  grade  of  steel,  the  required 
elongation  shall  be  measured  on  a  gauged  length  of  two  inches 
(2  inches)  and  may  be  five  per  cent.  (5  per  cent.)  less  than  that 
specified  %in  paragraph  No.  90,  as  determined  on  a  test  specimen, 
the  center  of  which  shall  be  one  inch  (i  inch)  from  the  'original 
surface. 

Eye  Bar  Tests. 

93.  Full-sized  tests  of  eye  bars  shall  show  12$  per  cent,  elon- 
gation in  fifteen  feet  of  the  body  of  the  eye  bar,  and  the  tensile 
strength  shall  not  be  less  than  55,000  pounds  per  square  inch. 
Eye  bars  shall  be  required  to  break  in  the  body,  but  should  an 
eye  bar  break  in  the  head,  and  show  twelve  and  one-half  per  cent. 
(i2j  per  cent.)  elongation  in  fifteen  feet  and  the  tensile  strength 
specified,  it  shall  not  be  the  cause  for  rejection,  provided  that  not 
more  than  one-third  (J)  of  the  total  number  of  eye  bars  tested 
break  in  the  head.     Eye  bar  material  shall  be  rolled  from  ingots 
from  which  at  least  25  per  cent,  has  been  cut  off  the  tops. 

Bending  and  Drifting  Tests. 

94.  All  steel  shall  conform  to  the  following  tests  : 

(d).  Rivet  steel  shall  bend  cold  180  degrees  flat  on  itself 
without  fracture  on  the  outside  of  the  bent  portion. 


42 

(e).  Structural  steel  shall  bend  cold  180  degrees  flat  on  itself 
without  fracture  on  the  outside  of  the  bent  portion. 

(f).  •  Medium  steel  shall  bend  cold  180  degrees  around  a  di- 
ameter equal  to  the  thickness  of  the  specimens  tested  without 
fracture  on  the  outside  of  the  bent  portion. 

(g).  Hot  and  quenched  bending  tests  may  be  made  at  the  dis- 
cretion of  the  Chief  Engineer  or  his  inspectors,  and  these,  when 
made,  shall  conform  to  the  requirements  of  d,  e  and  f,  above. 

(h).  Punched  holes,  pitched  two  diameters  from  a  sheared 
edge,  must  stand  drifting  until  the  diameter  is  one-half  larger 
than  the  original  hole,  without  cracking  the  metal. 

Test  Pieces  and  Methods  of  Testing. 

95.  Standard  test  specimens  of  eight  inch   (8  inch)   gauged 
length  shall  be  used  to  determine  the  physical  properties  specified 
in  paragraphs  Nos.  90,  91  and  92.     The  test  specimens  may  be 
milled  on  the  edges  with  a  parallel  section  not  less  than  nine  inches 
(9  inches)  long,  or  they  may  be  planed  or  turned  parallel  through- 
out their  entire  length,  and,  in  all  cases  where  possible,  two  oppo- 
site sides  of  the  test  specimens  shall  be  the  rolled  surface.    Rivet 
rounds  and  small  rolled  bars  shall  be  tested  of  full  size  as  rolled. 

Tensile  Test  Specimens. 

96.  Two  tensile  test  specimens  shall  be  taken  from  the  finished 
material  of  each  melt,  and  from  each  section  or  thickness  rolled 
when  these  vary  more  than  25  per  cent.,  but  in  case  these  develop 
rlaws,  or  break  outside  of  the  middle  third  of  the  gauged  length, 
they  may  be  discarded,  and  other  test  specimens  substituted  there- 
for. 

Bending  Test  'Specimens. 

97.  One  test  specimen  for  bending  shall  be  taken  from  the 
finished  material  of  each  melt  as  it  comes  from  the  rolls,  and  for 
material  three- fourths  inch   (J  inch)  and  less  in  thickness,  this 
specimen  shall  have  the  natural  rolled  surface  on  two  opposite 
sides.    The  bending  test  specimen  shall  be  one  and  one-half  inches 
(ij  inches)   wide,  if  possible,  and  for  material  more  than  three- 
fourths  inch   (J  inch)  thick,  the  bending  test  specimen  may  be 


43 

one-half  inch  (£  inch)  thick.  The  sheared  edges  of  bending  test 
specimens  shall  be  milled  or  planed.  Rivet  rounds  and  small 
rolled  bars  shall  be  tested  of  full  size  as  rolled 

Condition  of  Specimens. 

98.  Material  shall  be  tested  for  tensile  strength  in  the  condi- 
tion in  which  it  comes  from  the  rolls,  without  annealing  or  fur- 
ther treatment. 

Chemical  Tests. 

99.  In  order  to  determine  if  the  material  conforms  to  the 
chemical  limitations  prescribed  in  paragraph  No.  88  herein,  the 
contractor  shall  make  analyses  of  drillings  taken  from  small  test 
ingots,  and  the  results  shall  be  given  to  the  inspector  before  the 
material  is  shipped  from  the  mill.    The  Chief  Engineer  may  have 
check  analyses  made  at  his  option. 

Variation  in  Weight. 

100.  The  variations  in  cross  section  or  weight  of  more  than 
2j  per  cent,  from  that  specified  will  be  sufficient  cause  for  rejec- 
tion, except  in  the  case  of  sheared  plates,  which  will  be  covered 
by  the  following  permissible  variations : 

(i).  Plates  I2-J  pounds  per  square  foot  or  heavier,  up  to  100 
inches  wide,  when  ordered  to  weight,  shall  not  average  more  than 
2.\  per  cent,  variation  above  or  2^  per  cent,  below  the  theoretical 
weight.  When  100  inches  wide  and  over,  5  per  cent,  above  or  5 
per  cent,  below  the  theoretical  weight. 

(k).  Plates  under  12^  pounds  per  square  foot,  when  ordered 
to  weight,  shall  not  average  a  greater  variation  than  the  follow- 
ing: 

Up  to  75  inches  wide,  2j  per  cent,  above  or  2\  per  cent,  below 
the  theoretical  weight;  75  inches  wide  up  to  100  inches  wide, 
5  per  cent,  above  or  3  per  cent,  below  the  theoretical  weight; 
when  TOO  inches  wide  and  over,  10  per  cent,  above  or  3  per  cent, 
below  the  theoretical  weight. 

(1).  For  all  plates  ordered  to  gauge,  there  will  be  permitted 
an  average  excess  of  weight  over  that  corresponding  to  the  di- 
mensions on  the  order  equal  in  amount  to  that  specified  in  the 
following  table : 


44 

TABLE  OF  ALLOWANCES  FOR  OVERWEIGHT  FOR 

RECTANGULAR  PLATES  WHEN  ORDERED 

TO  GAUGE. 

Plates  will  be  considered  up  to  gauge  if  measuring  not  over 
i-ioo  inch  less  than  the  ordered  gauge. 

The  weight  of  one  cubic  inch  of  rolled  steel  is  assumed  to  be 
0.2833  pound. 

PLATE  J  INCH  AND  OVER  IN  THICKNESS. 

Width  of  Plate. 

Thickness  of  plate.  Up  to  75  inches.    75  to  100  inches.     Over  100  inches. 

Inch.  Per  cent.  Per  cent.  Per  cent. 

i 10  14  18 

5-16 8  12  16 

t 7  10  13 

7-16 6  8  10 

4 579 

9-i6 44  6i  8} 

S 468 

Overf 31  5  6J 

Finish. 

101.  Finished  material  must  be   free  from  injurious  seams, 
flaws  or  cracks,  and  have  a  workmanlike  finish. 

Branding. 

1 02.  Every  finished  piece  of  steel  shall  be  stamped  with  the 
melt  number,   and  steel   for  pins   shall  have  the  melt  number 
stamped  on  the  ends.    Rivet  and  lacing  steel,  and  small  pieces  for 
pin  plates  and  stiffeners,  may  be  shipped  in  bundles,   securely 
wired  together,  with  the  melt  number  on  a  metal  tag  attached. 

CAST    STEEL. 

Process  of  Manufacture. 

103.  Steel  for  castings  may  be  made  by  the  open-hearth,  or 
crucible,  process.     Castings  shall  be  annealed,  unless  otherwise 
specified. 


45 
Chemical  Properties. 

104.  Castings  shall  not  contain  over  0.05  per  cent,  of  phos- 
phorus, nor  over  0.05  per  cent,  of  sulphur. 

Physical  Properties. 

105.  The   minimum   physical   qualities   required   shall   be   as 
follows : 

Tensile  strength,  pounds  per  square  inch 70,000 

Yield  point,  pounds  per  square  inch 31,500 

Elongation,  per  cent,  in  two  inches 18 

Drop  Test. 

1 06.  A  test  to  destruction  may  be  substituted  for  the  tensile 
test  in  the  case  of  small  or  unimportant  castings,  by  selecting 
three  castings  from  a  lot.    This  test  shall  show  the  material  to  be 
ductile  and  free  from  injurious  defects,  and  suitable  for  the  pur- 
pose intended.     A  lot  shall  consist  of  all  castings  from  the  same 
melt  or  blow,  annealed  in  the  same  furnace  charge. 

Percussive  Test. 

107.  Large  castings  are  to  be  suspended  and  hammered  all 
over.     No  cracks,  flaws,  defects  nor  weakness  shall  appear  after 
such  treatment. 

Bending  Test. 

108.  A  specimen  one  inch  by  one-half  inch  (i  inch  by  J  inch) 
shall  bend  cold  around  a  diameter  of  one  inch  (i  inch)  without 
fracture  on  outside  of  bent  portion,  through  an  angle  of  90  de- 
grees. 

Test  Specimen  for  Tensile  Tvst. 

109.  The   standard  turned  test   specimen,   one-half  inch    (J 
inch)   diameter  and  two  inch   (2  inch)   gauged  length,  shall  be 
used  to  determine  the  physical  properties  specified  in  paragraph 
No.  105. 


46 

Number  and  Location  of  Tensile  Specimens. 

no.  The  number  of  standard  test  specimens  shall  depend  upon 
the  character  and  importance  of  the  castings.  A  test  piece  shall 
be  cut  cold  from  a  coupon  to  be  molded  and  cast  on  some  portion 
of  one  or  more  castings  from  each  melt  or  blow  or  from  the  sink- 
heads  (in  case  heads  of  sufficient  size  are  used).  The  coupon 
or  sink-head  must  receive  the  same  treatment  as  the  casting  or 
castings  before  the  specimen  is  cut  out,  and  before  the  coupon 
or  sink-head  is  removed  from  the  casting. 

Test  Specimen  for  Bending. 

in.  One  specimen  for  bending  test  one  inch  by  one-half  inch 
(i  inch  by  \  inch)  shall  be  cut  cold  from  the  coupon  or  sink-head 
of  the  casting  or  castings,  as  specified  in  paragraph  No.  1 10.  The 
bending  test  may  be  made  by  pressure,  or  by  blows. 

i 

Yield  Point. 

H2.  The  yield  point  specified  in  paragraph  105  shall  be  deter- 
mined by  the  careful  observation  of  the  drop  of  the  beam  or  halt 
in  the  gauge  of  the  testing  machine. 

Sample  for  Chemical  Analysis. 

113.  Turnings  from  the  tensile  specimen,  drillings  from  the 
bending  specimen,  or  drillings  from  the  small  test  ingot,  if  pre- 
ferred by  the  Chief  Engineer,  shall  be  used  to  determine  whether 
or  not  the  steel  is  within  the  limits  in  phosphorus  and  sulphur 
specified  in  paragraph  No.  104.    The  contractor  shall  make  these 
analyses  and  hand  the  results  to  the  inspector  before  the  castings 
are  accepted  or  shipped,  but  the  Chief  Engineer  may  have  check 
analyses  made  at  his  option. 

Finish. 

114.  Castings  shall  be  true  to  pattern,  free  from  blemishes, 
flaws  or  shrinkage  cracks.     Bearing  surfaces  shall  be  solid,  and 
no  porosity  shall  be  allowed  in  positions  where  the  resistance  and 
value  of  the  casting  for  the  purpose  intended  will  be  seriously 
affected  therebv. 


47 


Cast  Iron. 


115.  Cast  iron  shall  be  of  the  best  quality,  tough  gray  iron. 
Bars  one  inch  square  in  section  and  five  feet  (5  feet)  long,  when 
supported  by  knife  edges  four  feet  six  inches   (4  feet  6  inches) 
apart,  center  to  center,  must  carry  a  load  of  500  pounds  placed 
midway  between  supports  without  rupture.  Castings  shall  be  clean 
and  free  from  defects  of  every  kind,  boldly  filleted  at  angles  and 
the  arrises  shall  be  sharp  and  perfect. 

Timber. 

1 1 6.  All  timber  must  be  of  the  best  quality  of  long  leaf  yel- 
low pine,  white  oak,  Oregon  fir   (Douglas  fir)   or  pine,  sawed 
true  to  size  and  out  of  wind,  with  ends  cut  square  and  be  full  cor- 
nered.    Yellow  pine  in  all   square  sizes   shall   show  two-thirds 
heart  on  two  sides,  and  not  less  than  one-half  heart  on  two  other 
sides,  and  other  sizes  shall  show  two-thirds  heart  on  face  and 
show  heart  two-thirds  of  length  on  edges,  excepting  when  the 
width  exceeds  the  thickness  by  three  inches,  or  over,  then  it  shall 
show  heart  on  the  edge  for  one-half  the  length.    All  timber  must 
be  free  from  wind  shakes,  loose  or  rotten  knots,  worm  holes,  or 
other  defects  that  will  impair  its  strength  or  durability.    Oregon 
or  Douglas  fir  and  pine  shall  not  have  more  than  one  inch  of  sap 
on  corners. 

Creosoted  Timber. 

117.  When  creosoted  timber  is  specified  or  required  on  the 
work,  it  shall  contain  20  pounds  of  creosote  oil  to  the  cubic  foot. 
The  process  of  creosoting,  including  the  period  of  time  it  shall 
remain  in  vacuum  and  under  pressure,  and  the  amount  of  vacuum 
and  the  pressure,  shall  be  subject  to  the  approval  of  the  Chief 
Engineer. 

PAINT   AND    OIL. 
Linseed  Oil. 

118.  Linseed  oil  shall  be  pure,  aged  six  months  and  double 
kettle  boiled.    It  shall  be  free  from  all  adulterations,  and  not  con- 


OF  THE 

VERSITY  I 


48 

tain  any  fish  oil  nor  mineral  oil,  and  no  drier,  except  turpentine. 
No  more  than  10  per  cent,  of  turpentine  will  be  allowed  either  in 
linseed  oil  or  in  paint. 

Iron  Oxide. 

119.'  The  iron  oxide  shall  contain  not  less  than  90  per  cent,  of 
sesquioxide  of  iron  and  be  practically  free  from  sulphur  and  mois- 
ture. It  shall  be  finely  ground,  and,  if  lumpy,  shall  be  roasted,  to 
drive  of!  the  water. 

Paint. 

120.  Paint  will  consist  of,  pure,  double  kettle  boiled  linseed 
oil,  iron  oxide  and  pure  turpentine,  mixed  in  the  proportions  of 
8  pounds  of  red  oxide  of  iron  to  a  gallon  of  oil,  and  not  over  one 
gallon  of  turpentine  to  each  10  or  12  gallons  of  oil.     It  shall  be 
well  mixed. 

Inspection. 

121.  Every  facility  for  inspection  of  material  and  mixing  shall 
be  furnished  by  the  manufacturer,  and  the  Chief  Engineer,  or  his 
inspector,  shall  be  allowed  full  access  to  all  parts  of  the  establish- 
ment in  which,  and  at  all  times  when,  any  portion  of  the  work  is 
being  executed. 


VII. 
WORKMANSHIP. 


General. 


122.  All  workmanship  shall  be  first-class  in  every  particular, 
and  all  methods  used  during  manufacture  shall  be  satisfactory  to 
the  Chief  Engineer. 

All  material  shall  be  perfectly  straight  before  any  work  is  done 
upon  it  in  the  shop. 

Drilling. 

123.  Rivet  holes  in  all  material  J  inch  thick  and  over  shall  be 
drilled  from  the  solid.     Where  all  the  parts  are  f  inch  thick  or 
over,  they  shall  be  held  together  while  being  drilled  by  bolts  about 
three  feet  apart  in  holes  drilled  for  the  purpose.   These  holes  shall 
be  drilled  -J  inch  smaller  than  the  nominal  size  of  the  rivets  to 
be  used,  and  reamed  to  size  after  other  holes  are  drilled,  and  the 
work  shall  in  all  cases  be  taken  apart  and  any  shavings  between 
pieces  carefully,  removed  before  the  final  assembling  for  riveting. 
All  other  material  except  lateral,  longitudinal  and  sway  bracing 
shall  be  sub-punched  and  reamed.     When  a  member  is  made  up 
of  some  material  J  inch  thick  or  over  and  some  less  than  f  inch 
thick,  the  parts  that  are  f  inch  thick  or  over  shall  be  drilled  1-16 
inch  smaller  than  the  nominal  size  of  the  rivet,  and  those  that  are 
less  than  J  inch  thick  shall  be  sub-punched  -J  inch  smaller  than 
the  nominal  size  of  the  rivet.    They  shall  then  be  bolted  together 
and  reamed  as  in  sub-punched  and  reamed  work. 

Punching  and  Reaming. 

124.  In  sub-punched  and  reamed  work  the  holes  shall  first  be 
punched  J  inch  smaller  and  then  reamed  1-16  inch  larger  than 
the  nominal  size  of  the  rivets.    The  sharp  edges  must  be  removed 

•  from  all  reamed  or  drilled  holes. 

Reamed  work  shall  be  thoroughly  bolted  together,  so  that  no 


50 

shavings  will  be  forced  in  between  the  assembled  parts  during  the 
reaming. 

Accuracy. 

125.  All  drilling  or  reaming  shall  be  so  accurately  done  that 
after  assembling,  the  rivets  can  be  entered  without  further  ream- 
ing or  injurious  drifting. 

All  holes  for  field  connections,  except  those  in  lateral,  longi- 
tudinal and  sway  bracing,  shall  be  accurately  drilled  to  a  metal 
template,  or,  when  required  by  the  Chief  Engineer,  reamed  while 
the  connecting  parts  are  temporarily  put  together,  and  all  parts 
properly  match-marked. 

All  turn  tables  and  turn  tables  of  swing  bridges  and  other  com- 
plicated or  movable  structures  shall  be  completely  assembled  at 
the  shops  and  match-marked  before  shipment. 

Punching  of  Laterals,  etc. 

126.  Lateral,  longitudinal  and  sway  bracing  m?y  be  punched 
with  holes  1-16  of  an  inch  larger  than  the  size  of  the  rivets;  this 
shall  be  so  accurately  done  that  the  holes  will  come  truly  opposite ; 
if  any  hole  must  be  enlarged  to  admit  the  rivet,  it  shall  be  reamed, 
as  no  drifting  that  will  distort  the  metal  will  be  allowed.     Holes 
in  this  bracing  which,  in  the  structure,  are  continuous  with  drilled 
or  reamed  holes,  shall  be  reamed.     The  diameter  of  the  punch 
shall  not  be  more  than  1-16  inch  larger  than  the  nominal  size  of 
the  rivet,  and  the  diameter  of  the  die  shall  not  be  more  than  1-16 
inch  larger  than  the  diameter  of  the  punch. 

Planing  Edges. 

127.  All  sheared  edges  of  material  \  inch  or  over  in  thickness 
shall  be  planed  off  to  a  depth  of  3-16  inch,  or  as  much  more  as 
may  be  necessary,  to  remove  the  sheared  surface  of  the  metal. 

Rivets. 

128.  Rivets  shall  completely  fill  the  holes,  have  full  heads  con- 
centric with  the  rivet  of  a  height  not  less  than  0.6  diameter  of 
the  rivet,  and  in  full  contact  with  the  surface,  or  be  counter-sunk 


when  so  required,  and  machine-driven  when  practicable.  Rivets 
shall  not  be  used  in  direct  tension.  Built  members,  when  finished, 
must  be  true  and  free  from  twists,  kinks,  buckles,  or  open  joints 
between  the  component  pieces. 

Field  Rivets  and  Bolts. 

129.  Field  riveting  shall  preferably  be  done  by  pneumatic  riv- 
eters of  approved  make.     No  hand-driven  rivets  over  J-inch  di- 
ameter will  be  allowed. 

When  members  are  connected  by  bolts  which  transmit  shearing 
strains,  the  holes  must  be  reamed  parallel  and  the  bolts  turned  to 
a  driving  fit. 

Finished  Surfaces,  Joints  and  Fillets. 

130.  All  abutting  surfaces  of  compression  members,  except 
flanges  of  plate  girders,  where  the  joints  are  fully  spliced,  shall 
be  faced  true  and  square,  so  that  they  will  be  in  contact  through- 
out when  in  position  in  the  structure.     Tower  footings  and  bed 
plates  must  be  planed  true  on  all  sliding  surfaces. 

All  ends  of  stringers,  where  they  are  riveted  between  floor 
beams,  shall  be  faced,  and  shall  be  of  exact  lengths.  The  con- 
nection angles  shall  be  true  with  the  faced  ends,  or,  if  dressed, 
shall  not  lose  more  than  1-16  inch  in  thickness. 

All  bearing  surfaces  of  base  plates,  masonry  plates  and  vertical 
webs  of  pedestals  shall  be  planed ;  also  all  sliding  surfaces  of  shoe 
plates. 

Web  plates  of  all  girders  shall  be  so  arranged  as  not  to  project 
beyond  the  face  of  the  flange  angles,  nor  at  the  top  and  ends  be 
more  than  one-eighth  inch  below  the  face  of  the  angles  at  any 
point. 

All  members  shall  be  assembled  at  the  shops  and  match-marked 
when  required  by  the  Chief  Engineer.  Turn  tables  and  other 
movable  and  complicated  structures,  hip  roofs,  etc.,  shall,  with- 
out exception,  be  completely  assembled  at  the  shops,  in  operating 
order  for  movable  structures,  and  carefully  fitted  and  match- 
marked. 

Sharp  unfilleted  angles  will  not  be  allowed,  and  wherever  a 


52 

plate  or  shape  has  been  cut  into,  the  cut  must  be  finished  with 
sharp  cutting  tools,  or  with  chisel  or  file,  so  that  no  signs  of 
ragged  or  bent  edges  remain. 

Stiff  ener  Angles. 

131.  All  stiffener  angles  shall  fit  tight  against  the  flange  an- 
gles.    All  fillers  and  splice-plates  on  the  web  of  girders  and  riv- 
eted members  must  fit  sufficiently  tight  to  the  flange  angles    to 
exclude  water  after  being  painted. 

Pins,  Pilots  and  Rollers. 

132.  Pins  shall  be  turned  true  to  size  and  straight.     They 
shall  be  turned  down  to  a  smaller  diameter  at  the  ends,  and  shall 
be  supplied  with  one  pilot  nut  for  every  20  pins  or  less.     There 
shall  be  a  washer  for  adjustment  under  at  least  one  nut,  unless 
recessed  nuts  are  used. 

Rollers  must  be  finished  perfectly  round,  and  roller  beds  planed. 

Pin  Holes. 

133.  All  pin  holes  shall  be  accurately  bored  at  right  angles  to 
the  axis  of  the  members,  and  in  pieces  not  adjustable  for  length 
no  variation  of  more  than  one-sixty-fourth  of  an  inch  in  twenty 
feet  will  be  allowed  in  the  length  between  centers  of  pin  holes ; 
the  diameter  of  the  pin  holes  shall  not  exceed  that  of  the  pins  by 
more  than  one-thirty-second  inch,  nor  by  more  than  one-fiftieth 
inch  for  pins  under  three  and  one-half  inches  diameter. 

Eye  Bars. 

134.  Eye  bars  must  be  straight  before  boring;  the  holes  must 
be  in  the  center  of  the  heads  and  on  center  line  of  the  bars.    All 
bars  belonging  to  the  same  panel,  when  placed  in  a  pile,  must  al- 
low the  pin  at  each  end  to  pass  through  at  the  same  time  without 
forcing.     No  welds  will  be  allowed  in  the  body  of  the  bars,  nor 
in  the  heads. 

Eyes  of  laterals,   stirrups,  sway  rods  and  counters  must  be 
bored. 


53 

Upset  Ends. 

135.  All  bars  with  screw  ends  shall  be  upset  at  the  ends,  so 
that  the  area  at  the  root  of  the  thread  shall  be  at  least  10  per 
cent,  larger  than  the  body  of  the  bar.    Open  turn  buckles  will  be 
preferred  to  closed  sleeve  nuts,  and  shall  always  be  used  for 
counters. 

Screzv  Threads. 

136.  All  screw  threads  shall  be  United  States  standards,  ex- 
cept at  the  ends  of  pins. 

Annealing. 

137.  In  all  cases  where  a  steel  piece  in  which  the  full  strength 
is  required  has  been  partially  heated,  the  whole  piece  must  be  sub- 
sequently annealed.     All  bends  in  steel  must  be  made  cold,  or,  if 
the  radius  of  curvature  is  so  small  as  to  require  heating,  the  whole 
piece  must  be  subsequently  annealed. 


VIII. 
PAINTING. 

138.  All  scale,  rust  and  dirt  shall  be  removed  before  applying 
oil  or  paint  to  structural  steel,  and  no  paint  nor  oil  shall  be  ap- 
plied to  damp  surfaces.  All  surfaces  in  contact  with  each  other 
shall  receive  one  coat  of  paint  before  assembling,  and  all  other 
surfaces  one  coat  of  paint  before  leaving  the  shop.  All  finished 
surfaces  shall  be  coated  with  white  lead  and  tallow. 

After  erection  the  entire  work  shall  receive  two  good  coats  of 
paint,  the  color  of  the  second  coat  to  be  approved  by  the  Chief 
Engineer.  The  paint  must  be  carefully  and  evenly  laid,  and  well 
worked  into  the  joints  and  crevices. 

All  painting  shall  be  done  by  competent  and  experienced  work- 
men, satisfactory  to  the  Chief  Engineer  or  his  inspector. 


^-jjmA^fp* 

OF  THE 

UNIVERSITY 

OF 


IX. 

INSPECTION. 
Full  Size  Tests. 

139.  Any  full-sized  member  tested  to  destruction  shall  be  paid 
for  at  cost,  less  its  scrap  value,  if  it  proves  satisfactory.     If  it 
does  not  stand  the  specified  test,  it  will  be  considered  rejected 
material,  and  be  solely  at  the  cost  of  the  contractor. 

Testing  Machines. 

140.  The  contractor   shall   furnish   testing   machines   of   the 
proper  capacity,  and  shall  prepare  and  test,  without  charge,  such 
specimens   as   may   be  required  by   the   Chief  Engineer   or   In- 
spector. 

Access  to  Works. 

141.  Every  facility  for  inspection  of  material  and  workman- 
ship shall  be  furnished  by  the  contractor,  and  the  Engineer  and 
Inspector  shall  be  allowed  full  access  to  all  parts  of  the  establish- 
ment in  which,  and  at  all  times  when,  any  portion  of  the  material 
is  being  made  or  work  is  being  executed. 

Notice. 

142.  Timely  notice  will  be  given  to  the  Engineer  by  the  con- 
tractor of  when  he  is  ready  for  the  Inspectors,  and  the  Inspectors 
will  test  and  inspect  the  material  at  as  early  a  period  as  the  nature 
of  the  work  permits. 

All  material  must  be  inspected,  weighed  and  stamped  by  the  In- 
spector before  shipment.  Each  member  or  set  of  duplicate  mem- 
bers shall  be  weighed  and  invoiced  separately,  and  the  weight  of 
all  tools  and  erection  material  shall  be  kept  separate. 

All  pins,  nuts,  bolts,  rivets  or  other  small  details  shall  be  boxed 
or  crated,  so  that  they  can  be  easily  handled  in  unloading,  and  to 
insure  against  loss  or  damage. 


56 

Work  for  export  must  be  so  designed  that  no  member  shall 
exceed,  in  length  or  weight,  the  limits  fixed  by  the  conditions  for 
economically  handling  and  shipping ;  and  the  contractor  shall  ob- 
tain from  the  purchaser,  or  his  agent  or  engineer,  the  maximum 
lengths  and  weights  permissible.  Screw  ends  and  other  parts 
liable  to  injury  shall  be  properly  protected  by  wrapping,  or  other 
efficient  means,  to  the  satisfaction  of  the  purchaser,  or  his  agent 
or  engineer. 

Defective  Materials. 

143.  The  acceptance  of  any  material  or  manufactured  mem- 
ber by  the  Inspector  shall  not  prevent  its  subsequent  rejection  if 
found  defective  after  delivery,  and  such  materials  or  members 
shall  be  replaced  by  the  contractor  without  extra  charge. 

Interpretation  of  Drawings  and  Specifications. 

144.  The  decision  of  the  Chief  Engineer  shall  control  as  to  the 
interpretation  of  the  drawings  and  specifications  during  the  exe- 
cution of  the  work  thereunder. 


X. 

ERECTION. 


Extent  of  the  Work. 


145.  Unless  otherwise  specifically  agreed  upon,  the  contractor 
shall  furnish,  at  his  own  expense,  all  staging",  piling,  false-work, 
material  and  tools,  and  shall  erect  the  structure  complete,  ready 
for  the  ties,  if  the  ties  rest  on  the  steel  work,  or  ready  for  the 
rails  or  ballast,  if  the  structure  is  to  have  a  solid  floor.     In  cases 
of  renewal,  he  shall  remove  the  old  structure  without  unneces- 
sarily damaging  any  of  its  parts,  and  carefully  mark  and  inven- 
tory the  same,  noting  all  defects,  to  facilitate  re-erection.     He 
shall  load  the  old  material  on  cars,  or  carefully  pile  it  near  the 
work,  as  the  Chief  Engineer  may  direct. 

Conditions. 

146.  The  contractor  shall  notify  the  Chief  Engineer  when  he 
is  ready  to  commence  operations,  and  shall  not  begin  until  the 
Chief  Engineer  has  given  him  written  authority  to  do  so,  and 
approved  the  proposed  method.     All  operations  shall  be  so  con- 
ducted as  not  to  impede  or  interrupt  the  operations  of  the  road 
or  of  other  contractors,  nor  close  any  thoroughfare  or  waterway, 
nor  conflict  with  any  law,  regulation  or  ordinance  of  any  properly 
constituted  authority.     The  contractor  shall  obtain  all  necessary 
permits  and  comply  with  their  requirements. 

Watchmen,  Risks,  etc. 

147.  The  contractor  shall  furnish,  at  his  own  expense,  all 
watchmen,  flagmen,  and  other  safeguards  necessary  for  the  safe 
movement  of  trains,  as  directed  by  the  Chief  Engineer.    Flagmen 
must  be  familiar  with  the  rules  and  regulations  of  the  Railroad 
Company,  and,  if  the  contractor  desires,  they  will  be  furnished 
to  him  by  the  Railroad  Company  at  cost.   The  contractor  shall  as- 


sume  all  risks  of  accidents  to  men  or  material  prior  to  the  accep- 
tance of  the  finished  structure  by  the  Railroad  Company. 

Maintaining  and  Cutting  Track. 

\ 
'148.     The  contractor  shall  support  the  Railroad  Company's 

tracks  when  required,  and  this  work  shall  be  executed  in  exact 
accord  with  all  directions  of,  and  with  plans  that  shall  have  been 
approved  by,  the  Chief  Engineer.  Any  cutting  or  changing  of 
tracks  that  may  be  required  will  be  done  by  the  Railroad  Com- 
pany. 

Details  of  Erection. 

149.  The  contractor  shall  erect  the  structure  to  the  exact 
lines  and  grades  shown  on  plans,  and  as  laid  out  by  the  Chief 
Engineer.     Material  shall  be  handled  carefully,  to  avoid  injury, 
and,  when  injured,  it  may  be  rejected.    It  shall  be  piled  on  skids, 
to  keep  it  off  the  ground  and  clean.    Field  riveting  shall  be  done 
in  accordance  with  paragraphs  128  and  129.    At  the  completion 
of  the  work,  and  before  its  acceptance  by  the  Railroad  Company, 
the  contractor  shall  remove  all  timber,  false-work  and  rubbish, 
and  leave  the  site  unobstructed  and  clean. 

When  Railroad  Company  Erects. 

150.  In  case  the  Railroad  Company  is  to  erect  the  work  by  the 
terms  of  the  contract,  the  manufactured  material  shall  be  con- 
signed to  the  Chief  Engineer,  as  will  be  directed.    Any  extra  cost 
incurred  by  the  Railroad  Company,  on  account  of  defective  work, 
will  be  charged  to  the  contractor,  and  he  shall  bear  such  cost. 


XL 

HIGHWAY  BRIDGES  AND  BUILDINGS. 

General. 

151.  Highway  bridges,  buildings  and  roofs  shall  conform  to 
all  the  foregoing  requirements  of  these  specifications  wherever 
applicable,  except  in  the  following  particulars : 

The  floor  shall  consist  of  oak  plank  laid  on  steel  stringers,  or 
of  a  pavement  similar  to  that  in  the  connecting  streets  or  road- 
ways, of  macadam,  granite  blocks,  or  asphalt,  with  cement  side- 
walk pavement,  supported  on  concrete  floor  arches  or  slabs. 

Loads. 

152,  Highway  bridges  shall  be  proportioned  to  carry  a  live 
load  of  115  pounds  per  square  foot  of  both  roadway  and  side- 
walk reduced  by  one  pound  for  each  five  feet  of  length  of  span 
down  to  a  minimum  of  60  pounds  per  square  foot,  or  a  concen- 
trated load  of  ten  tons  on  two  axles  six  feet  center  to  center  and 
five  feet  gauge.    When  car  tracks  are  to  be  provided  for,  a  3O-ton 
electric  car,  30  feet  long  over  all,  with  a  wheel  base  of  19  feet,  on 
two  trucks  15  feet  center  to  center,  shall  be  used.    A  wind  load  of 
150  pounds  per  lineal  foot  on  the  unloaded  chord  and  300  pounds 
per  lineal  foot  on  the  loaded  chord  shall  be  provided  for.     One- 
half  of  the  latter  shall  be  treated  as  a  live  load. 

Floors  of  buildings  shall  be  proportioned  to  carry  live  loads,  as 
follows : 

Offices   75  Ibs.  per  sq.  ft. 

Public  rooms,  stations,  etc 125  "      "     "    " 

Warehouses  and  station  platforms,  from  150  to  300  " 

Flat  roofs 75"      "     "    " 

One-quarter  pitch  roofs 50  " 


6o 

The  latter  will  be  assumed  to  include  the  effect  of  wind  on  the 
roof  trusses.  All  buildings  shall  be  proportioned  to  resist  a  wind 
pressure  of  30  pounds  per  square  foot  of  exposed  surface. 

Working  Unit  Stresses  and  Allowance  for  Impact. 

153.  The    maximum    permissible    unit    stresses    in    highway 
bridges,  buildings  and  roofs  shall  be  the  same  as  those  given  for 
railroad  bridges  in  paragraphs  43  to  56,  inclusive,  except  those 
of  paragraph  52,  which  may  be  increased  twenty-five   (25)   per 
cent. 

For  highway  bridges  the  allowance  for  impact  or  dynamic  ef- 
fect shall  be  one-half  of  that  specified  in  paragraph  38. 

For  buildings  and  roofs  no  allowance  will  be  made  for  impact 
or  dynamic  effect. 

Sway  Bracing. 

154.  Through  highway  bridges  more  than  25   feet  in  depth 
shall  generally  have  sway  bracing  and  sub-struts. 

Minimum  Sections. 

155.  In  highway  bridges  no  metal  shall  be  used  less  than  5-16 
of  an  inch  thick,  except  the  webs  of  rolled  channels,  which  rnay 
be  i  of  an  inch  thick.     No  angles  less  than  3  inches  x  2j  inches 
x  5-16  inch  shall  be  used,  except  for  lateral  and  sway  bracing, 
where  they  may  be  2j  inches  x  2  inches  x  J  inch.     No  lateral  or 
sway  rod  shall  be  less  in  size  than  |-inch  diameter,  or  f  inch 
square.     No  lacing  or  lattice   bars   shall  be   used   less   than    i^ 
inches  x  J  inch,  nor  less  in  width  than  three  times  the  diameter 
of  the  rivets.     The  ratio  of  thickness  to  the  distance  between 
rivets  may  be  twenty-five   (25)   per  cent,  greater  than  specified 
in  paragraphs  79  and  80.     In  roof  trusses  no  metal  will  be  per- 
mitted under  ^  inch  thick,  no  angles  less  than  ij  x  ij  x  J  inches, 
and  no  rods  less  than  }  inch  in  diameter.     The  smallest  rivets  in 
highway  bridge  work  will  generally  be  f-inch  diameter,  and  in 
roof  trusses  ^-inch  diameter.     The  least  width  of  posts  in  pin 
connected  bridges  shall  be  limited  to  six  (6)  inches,  for  all  mem- 
bers subject  to  stress  from  live  loads. 


Punching  and  Reaming. 

t  ,6.     Rivet  holes  in  material  for  highway  bridges ^f  not  over 


withut  reaming,  the  work  being  done  as  required  by 
126 


Planing. 

157.  The  edges  of  sheared  plates  for  highway  bridges  and 
buildings  need  not  be  planed,  but  shall  be  sheared  true  and  even. 
The  ends  of  stringers,  beams  and  girders  for  highway  bridges 
and  buildings  need  not  be  faced,  but  the  connection  angles  shall 
be  square  and  set  to  exact  length. 

Building  Laws. 

158.  When  buildings  are  erected  within  the  jurisdiction  of 
established  building  laws  or  codes  they  shall  conform  to  the  re- 
quirements of  the  same  in  every  particular,  and  such  laws  or 
codes  will  supersede  these  specifications  when  and  wherever  they 
are  in  conflict,  but  not  otherwise. 


6o 


The  latter  will  be  assumed 
roof  trusses. 


38. 
allowance  will  be  made  for  impact 


Sway  Bracing. 

154.  Through  highway  bridges  more  than  25   feet  in  depth 
shall  generally  have  sway  bracing  and  sub-struts. 

Minimum  Sections. 

155.  In  highway  bridges  no  metal  shall  be  used  less  than  5-16 
of  an  inch  thick,  except  the  webs  of  rolled  channels,  which  may 
be  |  of  an  inch  thick.     No  angles  less  than  3  inches  x  2\  inches 
x  5-16  inch  shall  be  used,  except  for  lateral  and  sway  bracing, 
where  they  may  be  2\  inches  x  2  inches  x  \  inch.     No  lateral  or 
sway  rod  shall  be  less  in  size  than  f-inch  diameter,  or  J  inch 
square.     No  lacing  or  lattice  bars   shall  be  used  less  than    i| 
inches  x  \  inch,  nor  less  in  width  than  three  times  the  diameter 
of  the  rivets.     The  ratio  of  thickness  to  the  distance  between 
rivets  may  be  twenty-five   (25)   per  cent,  greater  than  specified 
in  paragraphs  79  and  80.     In  roof  trusses  no  metal  will  be  per- 
mitted under  \  inch  thick,  no  angles  less  than  if  x  if  x  J  inches, 
and  no  rods  less  than  f  inch  in  diameter.     The  smallest  rivets  in 
highway  bridge  work  will  generally  be  f-inch  diameter,  and  in 
roof  trusses  ^-inch  diameter.     The  least  width  of  posts  in  pin 
connected  bridges  shall  be  limited  to  six  (6)  inches,  for  all  mem- 
bers subject  to  stress  from  live  loads. 


6i 


Punching  and  Reaming. 

156.  Rivet  holes  in  material  for  highway  bridges,  if  under  § 
of  an  inch  thick,  may  be  punched  without  reaming,  as  specified  in 
paragraph  126.     Rivet  holes  in  material  f  of  an  inch  thick  and 
over  shall  be  punched  and  reamed  according  to  paragraph  124. 
Rivet  holes  in  all  material  for  buildings  and  roofs  may  be  punched 
without  reaming,  the  work  being  done  as  required  by  paragraph 
126. 

Planing. 

157.  The  edges  of  sheared  plates  for  highway  bridges  and 
buildings  need  not  be  planed,  but  shall  be  sheared  true  and  even. 
The  ends  of  stringers,  beams  and  girders  for  highway  bridges 
and  buildings  need  not  be  faced,  but  the  connection  angles  shall 
be  square  and  set  to  exact  length. 

Building  Laws. 

158.  When  buildings   are  erected  within  the  jurisdiction  of 
established  building  laws  or  codes  they  shall  conform  to  the  re- 
quirements of  the  same  in  every  particular,  and   such  laws  or 
codes  will  supersede  these  specifications  when  and  wherever  they 
are  in  conflict,  but  not  otherwise. 


Clearance  Diagram. 


SOOOlbs.par  Jin.  Ft.  of  hrack 

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wl 

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3?.  500 

p 

W                          arasoo 

VJ 

1                                    32500 

CJ 

4 

i                                  32500 

50000 

5 

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|                                SOOOO 

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1                                  SOOOO 

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0 

1                             32500 

'?                             ^2500 

p 

,                               32500 

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?                            32500 

! 

t 

1 

50000 

§ 

SOOOO 

y 

"*                                50000 

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°                              5OOOO 

'to 
E5000 

MOMENT   TABLE 

forJTwo  177.5  Ton  Typical  Consolidation  Engines  and  Tenders, 
Followed  J>y^  5000  pounds  per  lineal  foot 
*  For  one  rail. 
'  Weights  in  thousands  of  pounds.    Moments  in  thousands  of  ft  pounds. 

Number 
,of  * 
Wheel. 

Distance 
from  1* 
Driver 
Feet. 

Weight  on 
Wheel. 

Distance 
between 
Wheels 
Feet. 

Weight  between 
1*  wheel  and 
axis. 

Moment   of 
weights  between 
Ist  wheel  and 
axis. 

i 

6 

i  a.  so 

6 

1  2.50 

2 

0 

25.00 

5 

J7.50 

t  OO 

3 

'5 

25.00 

5 

62.50 

288 

4 

10 

25.00 

5 

87.50 

600 

5 

15 

25.00 

9 

1  2.50 

1  038 

6 

24 

6.25 

5 

28.75 

2O5O 

.       7 

29 

.      6.25 

6 

4-5.00 

2694 

8 

35 

6.25 

5 

61.25 

3564 

9 

-40 

6.25 

ft 

77.50 

4370 

O 

4-8 

2.5O 

8 

90.00 

5  790 

1 

56 

25.00 

5 

215.00 

7  31  0 

2 

6  \ 

25.00 

5 

24-0.00 

8385 

3 

66 

25.00 

5 

265.  OO 

9  585 

4 

7  1 

25.00 

9 

290.00 

10  910 

5 

80 

6.25 

5 

306.25 

13  520 

6 

85 

6.25 

6 

322.  5O 

15  051 

7 

91 

1  6.25 

5 

338.75 

16  986 

5 

96 

1  6.25 

0 

355.00 

1  8  680 

9 

06 

25.00 

0 

380.00 

22  Z3O 

20 

1  6 

25.00 

O 

4-05.00 

26  030 

21 

26 

25.00 

0 

43O.OO 

30  080 

22 

36 

25.00 

0 

455.00 

34  380 

23 

4-6 

25.00 

0 

480.00 

38  930 

24 

56 

25.00 

0 

505.00 

43  730 

25 

66 

25.00 

0 

53O.OO 

4-8  780 

26 

76 

25.  OO 

0 

555.00 

54  080 

27 

66 

5    25.00 

0 

58O.OO 

59  63  O 

28 

96 

25.00 

O 

605.00 

65  430 

-  29 

206 

25.00 

0 

630.00 

7  1  480 

30 

2  16 

25.00 

O 

655.00 

77  780 

31 

226 

25.00 

O 

680.00 

84330 

32 

236 

25.00 

0 

705.00 

91    130 

*  33 

24-6 

25.00 

0 

73O.OO 

98  180 

34 

256 

25.00 

0 

755.00 

05  480 

35 

266 

25.00 

0 

78O.OO 

13  03O 

*  36 

276 

*  25.00 

0 

805.00  ; 

ZO  630 

'37 

286 

-  25.00 

0 

830.  OO 

Z8  88O      . 

*38 

296 

25,00 

0 

855.00 

37   I8O 

*  39 

306 

-   25.00 

0 

880.0O 

45  730 

4-0 

316 

25.00 

0 

905.00 

54  530 

Maximum    Momerihs,    End  Shears 

and 

Floor   Beam  ReacHons. 
E  50  Loading. 

Momcnhs  in  hhousands  of  Foot  Jbs.    Shears  in  hhousands  of  ^bs. 

Span 
in 
fteh 

Maximum 
Momenh 

'   End 
Shear 

Fl  Bm. 
ReacHon. 

Span 
in 
Feah 

Maximum 
Mom«nh 

End 
Shear. 

R.  Bm. 
ReacHop 

10 

TO.  3 

37.5 

50.0 

46 

f03G.9 

103.5 

I5O.9 

u 

8Z  1 

4.0.9 

54..  6 

48 

i  »  1  O.O 

106.0 

156.0 

12 

IOO.O 

43.8 

58  3 

50 

1   182.2 

J08.9 

IGI.O 

13 

l  )&S 

46.1 

6).  6 

52 

I  268.  8 

1  (  /.6 

166.6 

14 

137.5 

4«.3 

<S5.2 

54 

1  3SI.3 

(14.0 

•  72.4. 

15 

156.3 

50.0 

G8.3 

56 

1  440.0 

116.3 

178.3 

16 

175.0 

53.  Z 

71.  < 

58 

1  528.8 

I  19.3 

t85.) 

17 

J93.B 

55.9 

73.5 

60 

1  624.4 

J22.O 

191.  C 

US 

Z(2.5 

58.4 

75.8 

62 

1  7E0.5 

us.i 

197.6 

19 

Z33.3 

60.5 

78.6 

64 

1  819.4 

128.3 

Z03.6 

ZO 

2575 

GZ.5 

81.9 

&0 

1  9Z4.4. 

131.3 

209.7 

2( 

282  S 

64..  3 

85.0 

68 

2029.4 

J34-.8 

215.6 

ZZ 

307.1 

65.9 

87.7 

70 

2  1  34.4 

138.) 

Z2J.3 

23 

331.8 

67.4 

90.2 

72 

Z  2.40.0 

14-1.7 

24- 

356.5 

69.3 

92.5 

74- 

Z  348.S 

145.4 

Z5 

3S/.3 

71.0 

94..  G 

76 

2  4  €3.5 

148.8 

26 

40G.O 

7E.6 

97.1 

78 

Z  5  80.5 

J52.I 

TresMcs 

Z7 

4-30.8 

74.1 

)00.l 

80 

2700.5 

155.3 

3O'6£6O' 

2S 

45G.<* 

75.5 

IO2.9 

82 

Z8E0.6 

158.6 

Spans 

29 

484-.  9 

7G.9 

1  05.4 

84- 

2945.6 

IC.1.9 

149.3 

30 

513.1 

7S.& 

107.8 

86 

3074.4 

165.1 

31 

54-1.1 

8O.5 

(  IO.6 

88 

3  ZO5.0 

/6S.4- 

A-Q'&GO1 

32 

5G9.3 

8Z.2 

1  13.8 

90 

3338.1 

171.6 

Spans 

33 

597.3 

83.7 

1  16.7 

92 

3470.0 

174.8 

164.3 

34 

£2  5.4. 

85.1 

1  19.4 

94- 

3S07.0 

(77.9 

35 

65  3.  8 

86.5 

»za.o 

96 

3  74Z.5 

181.0 

36 

685.  6 

88.2 

124-.4 

98 

38S3.  1 

184.4- 

37 

717.8 

89.9 

126.8 

100 

40Z50 

187.5 

38 

750.0 

91.4 

IZ.9.7 

105 

442  1.  9 

195.1 

39 

783.4- 

9Z.9 

J32.3 

UO 

4858.8 

202  S 

4-0 

8)9.4- 

94-.  3 

/3S.O 

MS 

530G.3 

2O9.9 

4Z 

891.9 

97.6 

•  40.0 

120 

5  767.5 

2)7.t 

44- 

964.4. 

100.7 

145.6 

125 

62456 

2Z4-.2 

>'•     OF  THE 

f   UNIVERSITY  1 


UniForm    Live     Loads   in   Pounds 
For     T~5QOOO. 
ONier  loadings    proportional. 

Span 
in 
Feet. 
S 

fcf 

V^ 

v^*-v^. 

Uniform  Liv« 
Load   per 
Fooh  of  TracK 
5O,pO  O 

V5**  Vs" 

10 

2.154-4. 

I.4-G78 

3.G22Z 

»3  804 

»5 

2.4662 

1.5704- 

4.0366 

)2  387 

20 

2.TI44. 

l.<54-75 

4..3S  I  9 

1  1  4^3 

25 

2.9£40 

1.7/00 

4-  .<S34O 

10790 

3O 

3.1072 

J.76Z7 

4..SG93 

IO267 

35 

3.271  1 

i.soas 

S.O797 

9  84-3 

40 

3.4200 

I.S4-93 

5.2693 

9  4-89 

4.5 

3.5SG9 

i.saeo 

S.4.4-Z9 

9   )86 

SO 

3.G.S4-O 

I.9I94> 

5.0094. 

8923 

55 

3.a030 

J.9501 

5.7S53  • 

8  €91 

<30 

3.914-9 

I.97SS 

5.a93B 

8484 

65 

4.0207 

2.0052 

6.0259 

8  298 

70 

4..  12  »  3 

2.O3OI 

6.  1  S  14V 

8  128 

75 

A.  2.1  72 

2.053a 

6.27  10 

7  973 

80 

4..  3089 

2.075ft 

S.3S4.T 

7  831 

85 

4.3968 

2.0969 

«.4-937 

T  TOO 

9O 

4.4S/4 

2.1  169 

6.S983 

7  ,575 

95 

4-.  5629 

2.1361 

6.6990 

74S4- 

100 

4.S4I  G 

2.  154-4. 

6.79«0 

73S7 

1  10 

4-.  79  14- 

2.  1889 

6.9803 

7  163 

120 

4.9324 

2.2209 

7.1633 

6990 

130 

S.OGS& 

2.ZSO7 

7.3IG  S 

6834 

14-0 

S.I925 

2.Z78T 

7.4-7I  2. 

6<S92 

150 

5.3)33 

2.3051 

7.6184 

6563 

160 

5.4288 

2.3300 

7.7SSB 

G4-36 

170 

5.5397 

2.  3536 

7.8933 

6334 

ISO 

5.64*22 

2.3762 

8.0224 

6233 

190 

5.74-89 

2.3977 

8.  !4-e>6 

6  138 

2O  O 

5.S4-SO 

2.4-183 

8.2GS3 

6049 

EZS 

G.OS22 

2.4-662 

8.54.S4. 

5849 

250 

G.2996 

Z.5099 

8.  8095 

SC-76 

273 

£.5030 

2.5501 

9.0531 

5STS3 

3OO 

<S  G94-3 

2.5873 

9.2.SI6 

5387 

32ST 

•S.B753 

2.6221 

9.4-974. 

S26S 

35O 

7.0473 

2.  <SS4-7 

9.7020 

5  1  54 

4-00 

7  3TOO             _| 

2.7150 

IO.O8  5O 

4960 

BOO 

7.9*00 

fc.airo 

10.7570 

4<SSO 

I 
I 

CO 
K 


-<J 

-cr 


£ 


-5     -i 


*     §    t 


| 

CX 


so 


cu 

a, 


I 


-8 


1 


g 


CO 


\\       H 


•«•*• 
c; 

1  >    J 

«  is  ^ 


CO 


03 
03 
CLj 

CO 


Co^FFici^rnbs    oF     Impacb 

when    bhere    is     no    rever-sdf. 

of   shress 

min 
max. 

Perce^  of 
LiVe  Load. 

mi  n. 
max. 

Pcrcenh  of 
Live  Load 

max 

P«rc«n»-oF 
Live  Load 

max. 

Perce^^oF 
Live  Load 

.00 

1  0000 

.01 

.990  / 

.£6 

.7937 

.51 

.6623 

.76 

5682 

o* 

.9604 

27 

.7674 

.se 

.es79 

.77 

,5650 

OS 

97O9 

.ff« 

.7S|3 

.53 

.<£53€ 

7S    . 

.56  IS 

.04 

.96»S 

29 

.7753 

54 

.6494 

.7S> 

5587 

.OS 

.952-* 

.30 

.7692 

.55 

.6452 

^o 

.5556 

.06 

9434 

.3> 

.7C34- 

56 

.<s*no 

.51 

.ssas 

07 

.9346 

.33 

.75  7G 

.57 

.6369 

.«2 

.5495 

.08 

.9259 

.33 

.7519 

.58 

6329 

.33 

.54<S4 

09 

.9174 

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.7-4-63 

.59 

.G2B9 

84- 

.5*3S 

10 

.909  / 

35 

.74-07 

<so 

<S250 

.85 

.5405 

1  | 

9009 

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.7353 

&\ 

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66 

537S 

.13 

.8929 

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.7299 

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«3 

BS50 

38 

.7246 

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.<S»35 

.88 

.5319 

14 

.S77E 

39 

7194 

.64 

.6098 

.89 

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.15 

.S696 

40 

.7143 

.<3S 

.6061 

90 

.5263 

16 

S6?l 

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.7092 

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GO  24- 

.91 

^Z3« 

17 

.«5A7 

^2 

.7042 

.<S7 

593S 

.92 

.5208 

.18 

.S4-75 

43 

.6993 

-SS 

5952 

.93 

.518  1 

.19 

.8A03 

.«*•* 

.6944- 

.69 

5317 

.94 

.5«55 

.20 

^333 

AS 

CS97 

.70 

.5882 

.95 

.5126 

.21 

S26A 

.««<£ 

.<5«49 

.71 

.SS48 

9<S 

.5102. 

-ZZ 

.S|97 

.*7 

SBG3 

.72 

^814- 

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.as 

.6130 

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.«757 

.73 

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5051 

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74 

.5747 

99 

5025 

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.50 

.6667 

.75 

.57  14 

1  00 

.SOOO 

,.         M 
M  *  m 

)  »  impach.=  Percenh  of  Live    Load. 
M»  Maximum    sHress  .' 
m  «  Minimum    shress. 

Coefficients    op     Impact 

when    there    is     a      reversal. 

of  shrcss 

j=. 

G 

Percenf-of 
Live  Load 

L 
G 

Percent-  of 
Live  Load 

k 

G 

Pcrcanf  of 
Live  Load 

L 
G 

PercenhoF 
Live  Load 

.00 

t  oo 

Ol 

1  .QZ 

.?e 

t.sz 

.31 

3.O2 

.76 

2.52 

.02 

I.O4- 

^7 

l.*4 

SZ. 

2.04- 

.77 

2   54- 

.03 

(.06 

.26 

1.56 

£3 

z.oa 

7« 

£.S«& 

04. 

1.08 

.33 

1.58 

.54- 

z.os 

.7» 

Z.5& 

.05 

I.I  O 

30 

1.60 

.SS 

Z.IO 

So 

Z.60 

.0® 

1.12 

Jl 

I.Ca<£ 

.5« 

Z.I  Z 

.81 

2.62 

.07 

1.14 

.32 

1.64- 

.57 

2.1* 

.8S 

£  A4 

joe 

1.16 

.33 

1.66 

.58 

2.16 

.83 

zee 

09 

/./a 

3* 

1.643 

.59 

2.18 

.a* 

Z.&8 

JO 

I.ZO 

.35 

1.70 

.60 

Z   20 

.8* 

2.70 

.1  1 

i  2a 

.3  « 

I.TZ 

.61 

Z.ZZ 

.8« 

Z.7S 

.13. 

J24- 

.37 

l.7<* 

.62 

2   Z4 

.87 

2.74 

.13 

l.2« 

.38 

1.76 

.63 

2.2<a 

.88 

Z.7« 

.14- 

I.Zfi 

.3d 

1.78 

.64- 

2   2S 

«9 

2.78 

.15 

1.30 

.4-0 

1.60 

.65 

2.30 

90 

Z.&O 

.»« 

1.32 

.4-1 

i.ae 

.66 

2J2 

91 

z.ftz 

17 

1.3* 

.42 

1.84. 

.67 

2.3* 

.9Z 

2.84 

.18 

i.9m 

.43 

I.8& 

.€<3 

Z.36 

.93 

2.86 

.19 

1  33 

4-4- 

I.8S 

.69 

2   3ft 

.94- 

2.88 

.20 

1.4-0 

4_5 

1.90 

.70 

2.4.0 

se 

2.90 

.HI 

1.42 

.4-6 

1  92 

.71 

Z  4-2. 

.9e 

2.92 

•tm 

J.44. 

4-7 

1.94 

.7e 

Z.44 

^7 

2.94 

.23 

l.4« 

A-a 

1.96 

.73 

2.4-Q, 

58 

2.96 

24- 

1.4.8 

4.9 

1.98 

.%t 

Z.4& 

^9 

2.98 

.Zff 

i.so 

.SO 

4  00 

.75 

Z50 

1.00 

3.09 

1  .     ) 

L-  r 
Q«  r 

l-l*Z   £ 
mpacf-  c    Per~ccnt   of    Livo   Load 

d. 

ind. 

Maximum  shress  of   grcafar   k 

Allowed  Stress  par  square 
inch  in  Compression. 

j_ 

r 

F 

1 

r 

F 

1 
__ 

F 

1 

r 

F 

. 

1  -~S>33 

31 

1  3933 

61 

11933 

91 

9933 

2 

ISS67 

32 

I3S<&7 

62 

1  I8-S7 

sa 

B8<K7 

3 

I58OO 

33 

438  OO 

63 

MS  O0 

93 

980O 

A 

IS733 

34- 

13733 

<S4 

II7S3 

94 

9733 

5 

(S<Sfe7 

•S3 

I3««7 

<S5 

1/667 

95 

9667 

<3 

156.00 

36 

I3GOO 

<S<3 

1  ICOO 

96 

9  GOO 

7 

ISS33 

37 

/3S33 

«7 

MS3S 

97 

9533 

8 

I5AG7 

38 

I3-KS7 

68 

M4-67 

98 

9467 

9 

154.00 

39 

13400 

69 

11400 

99 

9400 

IO 

15333 

4-O 

13333 

70 

11333 

too 

9333 

II 

JS26T 

4-1 

13267 

71 

It  267 

1  Ol 

9267 

12 

15200 

4-2 

t320O 

72 

11200 

102 

9  ZOO 

13 

15133 

4-3 

13133 

73 

II  133 

103 

9133 

14. 

15067 

4-4. 

I30<57 

74 

1/067 

104 

90G7 

15 

(5000 

4.S 

13000 

75 

II  000 

IOS 

9OOO 

16 

14933 

4-6 

\Z&33 

76 

10933 

»0<3 

3933 

n 

14867 

47 

IZ8&7 

77 

10867 

107 

8867 

i* 

t4soo 

48 

12800 

78 

10800 

108 

8800 

19 

1*733 

4.9 

13733 

79 

J0733 

109 

8733 

2O 

14667 

SO 

I2<67 

80 

I06«7 

tio 

8667* 

Kl 

14.600 

51 

tzeoo 

8! 

IOCOO 

III 

8600 

23 

14  533 

52 

J2533 

82 

10523 

112 

8533 

23 

144-67 

S3 

IE4-G7 

83 

I04<57 

113 

8467 

ZA 

14400 

54 

IZ400 

84 

10400 

114 

8400 

25 

14-333 

55 

I23J3 

05 

10333 

1  15 

8333 

26 

I4-E67 

56 

IZ267 

86 

I02€7 

116 

82G7 

27 

I4.20O 

57 

12200 

B7 

10200 

117 

ezoo 

28 

14-133 

58 

12133 

88 

10133 

118 

8133 

29 

14-067 

59 

I2.0G7 

89 

IOO67 

119 

8067 

30 

f4OOO 

60 

I2OOO 

9O 

IOOOO 

1  2O 

8000 

F  =  ISOOO—  GG§-  ^ 

F-  Allowed    sJ-rcss    per  sq.  in. 
/  -    Lenghh    in  inches 
r~    Radius  of    gyrof/on.* 

- 

1 

8 

1 

s 
s 

O 

1 

5 

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1/5 

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1 

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(0 

£ 

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00 

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2 

8400 

aazo 

1 

3 

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00 

9600 

! 

1 

9360 

9280 

9200 

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, 

Maximum  Bending  Momenhs  in  Pins. 

Exfrcme  fiber  stress  =  24ooo  Ibs   per  sq.in. 

D/am 

Area 

Momcnh 
in 
^nch  pound 

Diam 

Area 

Mom'cnK 
in 
Inch  pound 

Oiam 

Ar«a 

Moment- 
in 
Inch  pounds 

i 

.785 

E350 

^1 

(5.033 

»9730O 

7^ 

4-7.173 

I  OS  G  8  00 

l| 

994. 

33SO 

*i 

15/304 

214800 

7| 

48.707 

1  1  soaoo 

i* 

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4-600 

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1.485 

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2.405 

1  £7OO 

5i 

20.C.E9 

SI  7  ZOO 

at 

S&74B 

1  44-700O 

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2.761 

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5« 

E».C48 

3-4^000 

a* 

5a.420 

1  51  1800 

2 

3J*2 

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3<S590O 

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GO.  I3Z 

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3.  $4.7 

ZZ.700 

5^ 

Z3.7BB 

33SOOO 

ai 

Gt.a6£ 

1  €4-7  1  OO 

2* 

3.976 

ZG90O 

5f 

24.850 

41  9300 

9 

63.&17 

17/7600 

5* 

4,430 

31600 

5^ 

ZS.967 

447900 

^L 

94 

«S5.397 

I  790EOO 

z-k 

A-.  90  9 

3<o900 

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ESTIMATED   WEIGHTS 


OF 


STEEL    SUPERSTRUCTURES 

FOR 

BRIDGE    SPANS 


IN 
FEET 

WE/6HT  ///   POUNDS 

PER  FOOT. 

PEft  3  PAN. 

DECK  PL  A  TE  GIRDERS 

SINGLE  TRACK. 

L 

/4-.2L  +J4O 

I4-.212+/4-OL 

J«5~ 

G.37.S 

22^00 

SO 

$4-3.6 

42,4-80 

80 

'ttTSO 

IO2.OOO 

. 

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/4/,43~O 

THROUGH 

'  ft/VETED  SINGLE    TftACK 

SPANS-  SUB  DIVIDED  WAR  RE  M  TRUSSES. 

ce»TE& 

TO 

HL+800 

//U+800L 

1 

L. 

/0O 

no 

?efo. 

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22  f,  /OO 

120 

?,/  20. 

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272,^00 

14-0 

ZJ39  . 

327,600 

S60 

2.S60. 

+09,  fOO 

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Z,6€8. 

4-J~3/  9OO 

trs 

2,73  6. 

4  78,  500 

ISO 

2,780. 

SOO,  4-0  O 

/<?O 

2,88  7. 

£~4-9  .  IOO 

2OO 

3.00O. 

€OO,OOO 

This  table  was  prepared  for  E  50  loading  under  specifications 
that  give  slightly  heavier  girders  than  those  of  these  specifica- 
tions, and  above  weights  include  fillers  under  all  stiff eners; 


v,\i>R^^ 

OF  THE 

UNIVERSITY 


UNIVERSITY  OF  CALIFORNIA  LIBRARY- 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW 


/W#. 


MAR  4    1916 


-CE1VF 


161365 


